Supported Install Move to Proxmox? Looking for Advice!

Let me preface by saying my Linux OS knowledge is only as good as whatever YT video I’m watching. :smile: Hence the move, the descriptors on the HA website state only users very knowledgeable with the OS should be running the setup I’m running, and that’s not me!

I’m currently running on a “NUC-like” box I built running Ubuntu server 20.? Besides HA I’m also running Plex for music only.
Was considering going the Proxmox route. My concern is my CPU, it’s an Athlon 200GE (2 core, 4 thread 3.2Ghz) processor. I also have 8gb RAM, 240gb SSD.
From watching a YT video on this type of install, you allocate hardware to the VM. Does that permanently dedicate it to that VM or would it still be available if needed for the Plex VM?

Thanks in advance for your input!!!