rockarolla said my mind, except i wouldnt bother with the 5700x too, either stick to 5600 or go all out with 5800x3d, the non vcache 8 core has barely any improvement in gaming over the 5600.
thats a personal preference, i leave it unactivated. u only have to deal with the watermark and loss of customisation (eg system colours, desktop background), though u can dont connect to internet during setup and do the customisation before it realises it is unactivated.
taobao also have, even cheaper and still legit
dota2 isnt hard to run, so u can get a used gtx1060/rx580 for cheap and end of story.
not bad, but for just $20 more, u get the 5600 + 6700xt build which is faster and has more vram, which is a much better deal imo.
definitely not enough. if u insist on air cooling best to go for a dual tower like the noctua nhd15 or similar offerings from thermalright, though if u do long term core heavy workloads frequently water cooling is basically mandatory.
the msi aio edges ahead by a couple of degrees, based off one review i saw:
https://thepcenthusiast.com/msi-mag.../#7-msi-mag-coreliquid-c240-benchmark-results (scroll to results summary with other coolers, though its pitted against the slightly less budget ml240 mirror)
but for ur am4 system, a cheap air cooler is enough.