powered by a Raspberry Pi Zero 2 W
http://penkesu.computer/
Looks like there is enough space in there to upgrade to a Pi 4. That's probably how I'd go. The Zero 2 W is nice, but the 4 is quite a bit more capable. If it's going to be used regularly the extra performance would be worth it for the cost of a meal.
That looks like a fun build! Pretty cool little piece when done.