You guys might also be on the look out for refurbed minisforum 795s7's as I was able to grab one of these a few weeks ago for a little less that current offerings. Basically same board but with case and sff powersupply. Note unless you are gunning x3d AM4 cpu or already have AM5 then a stock...
From experience, I would say an Nvidia GPU is going to be the best bet in the long run as it will just work, I am currently running a 3080RTX with 10gb with 9700x AMD 8c16t cpu (which is almost like base line AMD am5 chip) and 32gb ddr 5. I have this mated up to a 77" LG C1 oled @ 120hz/ VRR 4k...
Yep your best bet is to drop component voltages thus wattage to generate heat. Also if you can duck heat output external to your room it could also help a lot more than portable ac. Remember even though you are pulling the 600w off your rig it just dumps it to ambient room. Not sure we really...