Have you looked to see if StartOS is an option to solve your future needs? I run it on an old iMac pretty well. Haven’t hit the limitations you have yet.
Discussion
I have. We use Umbrel for self-hosting things like media and documents, and Start9 for Bitcoin only. Remote access has been a key factor – Umbrel’s use of Tailscale to access files remotely is super easy. StartOS, on the other hand, only uses Tor, to my knowledge, for remote access, which is slow. That’s why we lean on Umbrel. However, if there is a better way to remotely access StartOS, I’d love to try it.