Separate services from NAS?

Currently have an old i3 that has a couple hdd in raid 0 running plex. Was going to switch to a proper NAS and was going to have a NAS and then a proxmox to run docker for plex/home assistant, backups, etc…and any other VMs I may want and NAS would just have 2 pools one for backups and one for media. I really was trying to have a “loose” budget of around $1500, but would it be better to not separate out the NAS and just have 1 server do it all? I dont really have more than 2 or 3 streams at max, but I did want to get to hardware transcoding as well with a p400 maybe. Plan was a rack, pdu, 24 port poe switch to eventually support some APs to replace my orbi mesh, a proxmox server and a nas server with another 4-6 drives along with repurposing my 4 (2TB WD Red drives). I know that’s probably going to run closer to 1800 or more. Thinking maybe I could splurge on 1 server and move things off at a later date and start smaller?