Unifi-like auto IP discovery on layer 2 network (IPAM)?

I'm managing a small business network, think about ~80 connected end hosts both wired and wireless. Currently using the Unifi controller software as the DHCP server (with a Unifi router) but we're planning to eventually move away from Unifi, probably more enterprise grade or opensource router/firewall like OPNsense/PFsense.

I really love how I can have someone plug any device in or connect to the APs and 20 seconds later have its DHCP-assigned IP address and it's uptime on a nice GUI. I also like that I can assign static mapping to said IPs and basically make them "static" forever from the Unifi GUI, rather than through every single device individually, and making IPAM a breeze. It just makes my life that much easier, but I'm locked in the Unifi ecosystem to get it.

What is the best cross-platform, non-Unifi way to achieve something similar? Can be through command line too, but just need some advice as I've become used to this way of doing it through Unifi GUI. Bonus points if it supports DHCPv6 as well (Unifi does, but doesn't do static mapping like it does for IPv4 and it doesn't list the IPv6 addresses in the GUI either).

Thanks!