If you had to redo your self hosting setup, what would you do differently this time around?

To be honest, nothing. Running my home server on a nuc with proxmox and a 8 bay synology Nas (though I'm glad that I went with 8 bay back then!).
As a router I have opnsense running on a low powered mini pc.

All in all I couldn't wish for more (low power, high performance, easy to maintain) for my use case, but I'll soon need some storage and ram upgrade on the proxmox server.