yes possible, see the value gaming rig reco in first post; possible to fit a similar build but with better quality parts within 1k with a cheap case (which is something aftershock does anyway). while the storage is halved at 512gb, top up to 1tb is less than $20, and the sn570 is significantly better than the nm620. u also get a b550 opposed to a520, which opens up pcie gen4 so gen4 nvmes (which can be way faster) become a viable option and/or upgrade path, and u also dont suffer performance loss on gpus with less than 16 lanes like the rx7600. u also get a much better psu (u should avoid the montech ap if possible) and ram with slightly tighter timings.
if ur ok with aftershock though, their 5600 + 6700xt for just a $60 top up is quite unbeatable. u get a (marginally) better psu, and not only does the 6700xt offer 10% more performance and 50% more vram than the 7600 for 6% more money overall, u literally cant find it in sls anymore.
what happens when u press the power button? fan spin only?
yeah why not, as long as ur case can fit atx mobo. if reusing ssd then no need to reinstall windows, just maybe reenter activation key. it is still recommended though.
