Kaylon

You can always use Wit of Death's Herald to get brilliant (but of course you need to rest).

Bear with Pain Block from cipher has already very good survivability. And if you add Exalted Endurance, Ancient Memory, Her Courage... (from a herald) he becomes nearly immortal.

Chanter/ranger with the Red Hand can deal decent single target dps and also increase pet's survivability with buffs/chants. But IMO the most fun build for a ranger is the arcane archer/cipher with Frostseeker - crazy accuracy and AoE damage (and also great buffs for the pet).

Troubadour/priest is great since you can extend all these buffs and benefit also from Muse of Mystery+Brisk Recitation+Brilliant stacking to spam invocations. (Not sure if Attuned Channel from The Weyc's Wand stacks with the other PL buffs). And Her Revenge Swept Across the Land is a very efficient invocation - low cost with high damage potential against single/multi targets.

My personal opinion is the first PoE sold well because it was advertised as the spiritual successor of BG and many people had great expectations. Since PoE2 wasn't a big improvement over the first, mostly players who enjoyed the first bought it. And for me, the fact that most people don't even finish their game should be the main indicator for developers, not the sales...

You can give WotEP to Rekke (fighter/barbarian).

I will give an example of arbitrary - there's no way to predict if a dot will stack with itself without testing. Some stack, some just refresh their duration while others can't be applied until the first expires.

I didn't play P:K yet, but I can understand why Deadfire wasn't a big success, because I had a very hard time myself getting into it. Overall the story is pretty weak (I was never hooked by it), the hero lacks the epicness of this kind of games (being a watcher isn't a big deal overall/doesn't make you feel very special) and the game system is very obscure and unintuitive (many rules feel completely arbitrary/are hard to understand).

You can compare games to movies... The movies considered "best" by the critics are rarely the ones with the most entries. Which one is "better" is debatable because the "elite" (critics) look for something else in movies compared to "common" (most) people. When both parts are pleased then you really have a jewel...

Have you identified the shrine first? Maybe try also other shrines... If it doesn't work then it was probably patched.

Arcane Archer/cipher (no subclass) with Frostseeker (and Essence Interrupter with modal) is really great. The cipher will add more damage/accuracy/defenses/penetration, as well as plenty of buffs for your pet. With your accuracy (+ ability to debuff enemies deflection) Frostseeker will proc like crazy and the AOE also contributes to your focus generation (allowing you to cast spells at leisure).

Use the explosive barrels and find a spot where the enemies can attack one at a time (in melee).

How? Also, how do you expect to trigger Blade Cascade? Anyway, you can't expect to beat the mega bosses with Vanishing Strike - you have to use Gouging Strike and wait...

The buff should be modded to work like Empower...

Paladin/Bloodmage and Paladin/Troubadour are the strongest for solo/party, right from the beginning. However, like for PoE1, you need good knowledge of the game to use them at their full potential. Paladin/Troubadour is probably easier to play when you start for the first time.