I’m looking at tilemap studio and it looks promising; however there aren’t any examples in the docs about how to incorporate it into a GBA game. Does anyone have an example of using a map created in this program and incorporating it into a GBA build?

You should probably ask in that repository how to export in the GBA format. You should take a look at this to see how to load data: https://www.coranac.com/tonc/text/regbg.htm#sec-demo

Thanks; I got a decent answer on their issue tracker, though their docs could certainly be improved.

A simple example for anyone who’s curious: https://git.sr.ht/~technomancy/liquid-runner-3/tree/master/item/Makefile#L51

Importing a sprite sheet from TIC-80 turned out to be pretty easy using gbagfx.