For starters I'd file a bug against pihole so they support both doas and sudo or drop them altogether and make you use either sudo or doas when executing the script. A hard dependency on sudo is really weird imho.

I have had a desktop and a laptop on a basic compatibility script, that only implements sudo <command>, for a long time, and not had any issues.
And I installed and compiled a bunch of random stuff.
I would be very surprised if there were issues.

I recommend you set up some log file to log calls to sudo, so you can judge how much that layer is even needed.

Try it, find out