I'd basically recommend going similar to the medium build from Sarex's guru3d article.
R5 2600- can go 2600x for the better cooler and automatic overclocking, probably not worth it tho
16GB DDR4 RAM (3000MHz+, any reputable brand on the QVL. Don't bother with B die, not worth the premium)
RX 580** (fine for 1080p/60Hz, assuming 60Hz. Think they have a pretty good game bundle with them too at the moment)
550W or higher modular/ gold PSU (any decent quality unit like EVGA G series or recent Corsair CXM, check out a PSU tier list if in doubt)
Crucial MX500 SSD
That would be a fair bit under budget, I'd put any leftovers towards a monitor/ GPU upgrade later on.
*X470 if you need the features, but a Tomahawk's specs are as good as or better than most cheap x470s. MSI has done an excellent job with their 400 series boards.
**IMO the GPU market is pretty meh at the moment, so I'd tend to recommend a cheaper card rather than an overkill card especially since RTX is still at meme level adoption/ performance. nVidia's 1660 is also close to release and may be worth consideration. If a monitor upgrade is likely within a year a 2060/70/80 (or Vega 56/64 if you don't mind tinkering, they require a good quality 550W+ PSU though) should be considered, depending on resolution.