I have a few vlan subnets, one for IOT devices (smart junk, automation, media players etc), one for general LAN devices (mostly computers, NAS etc), one for VMs and other services and one for guest access. all with their own fairly simple firewall rules to eachother and to the web. there are also matching Wifi networks for IOT, Main and Guest that are on those Vlans.
As for DHCP, I tend to set the DHCP ranges for xxx.100 - xxx.254 and anything below 100 is for static allocations. all in standard 192.168.x.x ranges, no need to go bigger than that. I only have IPv6 for the VMs for testing cause i’m still learning how to use that properly and safely.