First thing's first, this amount of power in this small of a case requires patience to figure out the parts, what works with them, and a bit of comfort in allowing things to get hotter than you're probably used to. Easiest thing you can do to reduce heat is go and find a stable offset, right now I just have a quick and dirty -.05v offset and that's it, and it's helped my system dramatically in terms of heat. In terms of idle my CPU depending on the day(I live in Texas, it gets really hot) hovers around 40-41c which is perfectly fine. In daily normal use I'm around 46-50c. Gaming anywhere from 55-75c but usually in the mid 60's, low 70's is the norm depending in the title.
CPU: AMD - Ryzen 5 3600 - Adjusted the build and went with a 3600 over a 3700x for a few reasons. I do hardly anything other than gaming on my PC. I don't stream, I do very little work that a 3600 couldn't do. Given the 3% performance difference, there simply isn't a reason for me to go for the 3700x at an additional $130 in price for that little benefit, plus the temps are cooler.
Cooler: CRYORIG - C7 Cu 40.5 CFM CPU Cooler - This was the game changer. A cooler capable of handling the necessary watts I needed, and a cooler capable of dispersing the heat at a fast enough rate to allow me to utilize my CPU to its full potential. With this, I'm not forced to do any downclocking/undervolting, and under a full gaming load, I'm sitting right around 68-70c, which is right where I want to be, and where I expected to be.
Motherboard: Asus - ROG STRIX X470-I GAMING Mini ITX AM4 Motherboard- Amazing build quality, but not the easiest board I've ever worked with. I've used nothing but ASRock boards before, so this was a different beast to me, but overall I'm very pleased with it.
Ram: G.Skill TridentZ RGB 3200 - fast, runs at advertised speeds, no issues to report, and it's sexy as hell.
Storage: Samsung - 860 Evo 1TB M.2-2280 Solid State Drive - Easy enough, works great, fast, really affordable option for a huge SSD.
GPU: Radeon VII - fast and relatively quiet, stays pretty cool, overall a solid GPU, albeit an expensive one. I'm looking to replace with a 5700 XT when the partner cards become more available.
Case: Fractal Design - Node 202 HTPC Case - My love, so beautiful, so slim, so sexy. Easy to work with, outside of the back part of the case, that thing is a pain in the *** to get off the first time.
Power Supply - Corsair - SF 600W 80+ Gold Certified Fully-Modular SFX - It's a power supply, it works, it's reliable, that's what I want. The cables are stiff as hell and require some bending though to get working in the Node 202 properly.
Case Fans: 2x Noctua - NF-F12 PWM chromax.black.swap 55.0 CFM 120mm Fan - they keep my GPU cool as a cucumber, well, as cool as it can be.
Monitor: Gigabyte Aorus AD27QD - BEAUTIFUL BEAUTIFUL BEAUTIFUL!!! I've been waiting on a monitor like this for YEARS for AMD. The holy grail of gaming, 1440p, 144hz, IPS, Freesync. It also comes with HDR, it's cute, and provides some benefit, but nothing that I'm overly in need of. For HDR gaming I have my LG C8 in the living room :D
Overall I'm very happy with my system and everything that I've added to it/put in it. The saved desk space for me is a huge bonus, as I'm fairly OCD and obsess on clutter. Given the amount of power in this case, there is going to be a bit of give and take. It's not reasonable to assume a case of this power is going to perform thermally to what you're used to in a big open air case. There will be heat, it's about learning how to manage that heat. If I could give anyone advice on building in this case it's be patient, you'll run into crashes, errors and tons of frustration at first but it's worth it in the end.