What's up ServerBuilds! -- First time. Rack or no rack?


I have nearly collected all the parts for my first server build. Outside of the motherboard and sas controller the parts are from an unbelievable deal on a 3900x gaming pc and old drives I have used for manual backups. The general plan was to run some sort of nas software with plex on top of proxmox. I have been leaning toward this plan for the last 48 hours due to the vm/tinkering advantage proxmox appears to have over running containers in a baremetal unraid install for example. If this isn’t a good idea or there are better solutions I am all ears!

Parts list:
ASRock X470D4U (I wanted full remote access because I am away from home frequently)
32 gb non-ecc memory
LSI SAS 9211-8i
Quadro P400
650 watt platinum psu
2x500gb ssd
Collection of drives in varying sizes.

I have been in tutorial/build guide hell for over a week now haha so please excuse me if these questions are redundant.

A couple of questions: