What do you like in WOTR? I'm playing an angel oracle atm, getting wrecked early game unfair. Played a sylvan sorcerer lich before, seemed a lot easier. Are you playing deadfire turn-based or RTWP? Most of us do RTWP and some builds work better/worse depending on this
I can't seem to separate your paragraphs with double <enter> like normally so I'll just respond with numbers.
You should try playing solo if the game is too easy. Or maybe a party of 2 or 3. Or add some magran's fire challenges. Like you I played Deadfire a bit when it came out, got bored, never finished the game, played other stuff, came back to it less than a year ago and started messing with solo builds and magran's fires. Well-built full parties are going to be overpowered in general. I've found builds that can solo everything with magran's fire challenges and deadly deadfire hardcore (even without cheese strategies), so if you add a full party to this type of character it could be overkill.
1) Why is tuotilo's palm a must? That shield is really only going to help you with a sage. Otherwise you're better off not using shields or if making a mage tank like arcane knight using akola's apex ward.
2) sage - you can use FF with the lance but the lance won't distribute the FF attack, it just works as normal single target FF, but if you trigger swift flurry or heartbeat drumming you do hit everyone. FF sages are best as tanks, using FF to heal themselves and wearing heavy armor while casting fast defensive wizard spells and using iron wheel. Helwalker sages are high DPS build, but you may need to deify yourself (potion of final stand + wall of draining) to not die given their squishiness. The lance is particularly good since it distributes monk abilities like stunning surge and skyward kick. In fact if you use it on a group and crit more than one enemy you can get back more than the cost of the surge. If your accuracy is high enough you can use stunning surge in this way to quickly rebuild mortification. Wounds build easily enough from blood sacrifices and damage, which is why it's best if you have a potion of final stand so you can really avail yourself of this incredible wound generation. Alternatively you could stay back and nuke things using dichotomous souls as fodder and +might for more spell damage. Shattered Pillar could possibly work okay with the lance since it hits multiple enemies, but I haven't really tried it. Any of these can solo the game once you get wall of draining, provided you use potions of final stand.
3) tactician blood mage can easily solo the game. DPS isn't as high as helwalker/blood mage but you are infinitely more tanky and brilliant is trivial to achieve if you have on berath's challenge. Just going invisible triggers brilliant, so if you're down on resources just use arkemyr's brilliant departure. You also get back fighter resources interrupting spells and abilities so the lance is weapon of choice given its AOE crush interrupt-on-crit attack, and you can also use mule kick with the lance to mule kick groups of enemies, which is pretty fun since it only takes a graze to kick them into the air. Can also interrupt with slicken and chill fog, I like to use these spells a lot with tactician battlemage. To stay alive unbending + wall of draining will eventually make you effectively immortal the way unbended stacks with itself, and even pre wall of draining it is extremely effective with max INT. Should note there are other ways to get tenacious/energized, like using slayer's claw. If you cycle the weapon it upgrades might inspirations, so even a "strong" inspiration (e.g. from lover's embrace) can be upgraded to energized and extended via wall of draining. Lance already interrupts on crit though so there's not a huge advantage of energized over tenacious unless you're casting offensive spells, which you mostly wouldn't need to do with a battlemage. Because of easy procs of brilliant you can theoretically cast lots of spells, you just wouldn't want to because mule kicking things with the lance is much more effective.
4) warlock - haven't played this one as much but it's interesting, would just go blood mage / barbarian personally (berserker if you use potions of final stand). Can theoretically do decent damage with lance + carnage, barbaric smash and crushing blow can be used with lance on groups to get back resources or recover very fast. Frenzy and other barbarian passives mean you attack very fast. Accuracy is not great. Savage Defiance can be extended with wall of draining for decent heals, but nothing approaching unbending so it's squishier unless you use potions of final stand. Should be noted with the lance though you can attack from behind your tank since it's a reach weapon, so you don't really need to facetank things. Can also do some casting with brute force and morning star but I pretty much always prefer the lance.
5) blood mage / fury is a top tier elemental caster, but you'll find it rather squishy. I guess blood mage / ancient (or animist or lifegiver) could be interesting once you're able to extend animal forms, though you will won't be all that tanky. There's some interesting caster interactions like combusting wounds with infestation of maggots, and lance of the midwood stag makes a superb stat stick for +2 power levels and woodskin. I generally prefer straight druids for their amazing tier 8/9 spells but if you want a caster sorcerers are pretty versatile
6) bellower / blood mage is quite strong once you get wall of draining since you can extend the bellower bonus power level and spam her tears. Probably works better with a wizard though due to the weyc items, sasha's singing scimitar, and least unstable coil, and their interaction with empowering abilities which allows you to get all tier 3 inspirations. bellower/wizard reaches its full power very late though since these are mostly dlc items. If you want to just cast tons of high damage spells this is a good choice, not as good as the others for beating things with sticks.
Others you didn't mention
7) blood mage / priest of skaen - can easily solo the game due to barring death's door, salvation of time, and wall of draining. Used in many ultimate runs. One of the most versatile builds, probably best suited for solo.
8 ) blood mage / ranger - doesn't seem at first glance to have a lot of synergy but can give you a lot of accuracy bonuses and the pet makes soloing easier. @Boeroer has a geomancer build somewhere but I don't recall where it is.
9) blood mage / rogue - blood mage / assassin in particular is quite powerful, since you can use shadowing beyond and assassinate over and over. Can easily solo the game though personally I find the combat a little reductive. Blood mage / streetfighter is also interesting. You'll probably need potions of final stand but does a great deal of damage with streetfighter buffs and lance, also you can extend escape with wall of draining to make it pretty tanky. And again the lance applies abilities like gouging strike to everyone in the AOE.
10) arcane knights make top tier tanks. See this build for example a tank/caster (I'd probably go human not fire godlike unless playing with BPM)
11) Hierophants are incredibly strong. Blood mage / ascendant can extend ascended stage with wall of draining and murder things with cipher spells or just use bonus damage and lance, though this comes late and I don't really know how well they play before WOD. Blood mage / psion is a great caster, and there's a build I made here, though I haven't played it nearly as much as melee hierophants
My favorite hierophant by far though is blood mage / soul blade. As far as I know this is the highest melee DPS build, possibly highest DPS period. I used it for an ultimate run. See this post I made and its links if interested