the new cooler worked! no more power-downs, temps are down to 81.5c max, and frame rate doesnt get gimped by the cpu anymore. my ram is still pretty poor and seems to be hurting performance in a few games, but nothing drastic (outside of stutter in Control). i'll upgrade that further down the line though; the gpu, psu, and cooler combined cost me $850 usd. thank god it wasnt for nothing in the end
Good news, it is a toasty chip at full load unfortunately. Since you have a Z390 you could always apply a small undervolt to bring the temp down more if you felt comfortable doing that, but 80C is pretty normal.
If you upgrade RAM at a later date your best bet is for 32GB 3600Mhz.