If you want lots of nvme, lots of sata, lots of ram and lots of ability to power drives then you’re not looking at a minipc anymore.
Would suggest you do the same I did — climb onto ebay and look at the AM4 systems that gamers are dumping. AM4 is aging out of gaming space but for NAS/proxmox duty they’re aging like fine wine. Look for one that has is X570 and has bifuraction support on the X16
Ahh, I might want to explore that one day too.