Have been using Emacs for over a decade, and I’m fairly happy with it.

This is true, but it’s not the quantity of engagement that matters, it’s the quality. Also the fediverse isn’t necessarily intrinsically better than a hellish corporate site, but it’s operated more democratically which tends (not always) to lead to better quality overall.

Easiest way would be to set up a new instance on a subdomain. Federation problems will be due to keys for the domain being cached on other instances, including for the instance actor.