I run 2 instances of pihole/unbound as lxcs on my main server and local back up, works great.

If I didn’t have the two big boxes I’d use my pi4/zero2 to run two instances of pihole/unbound.

If I didn’t have my pis, I’d run 2 instances of pihole/unbound on literally anything I could install it on.

What I’m saying is that I consider pihole/unbound to be essential infrastructure at this point. I’m also trying to say I’ve broken my only instance of pihole enough times to understand the importance of redundancy.