It sounds like you have open walls in the garage so far, so my main advice is simple. You don't have enough outlets. There are never enough outlets, and they're never in the right place. Once you put up drywall, you're locked in, so seriously consider putting a stupid amount of outlets in before that step. Maybe you'll want to hang a TV in the corner of the ceiling. You might want a high outlet. What about that projector? Ceiling outlet. Powered screen? Another ceiling outlet. Workbench, bar, fridge, freezer, margarita machine, disco ball, whatever.No walls to frame, just insulate, drywall, mud, paint, etc. Outlets are already in place.
Maybe you want wired internet in there. Surround sound? Security cameras?
Also, depending on your building code, you may be able to use something other that drywall. When I closed up my garage walls, drywall was very expensive. Not sure if that's still the case. I used OSB because it was 1/2 the price. Once I putty'd the screw holes and painted it, it suits me fine.
For insulation I went with Rockwool. It's better than the fibreglass stuff because it won't rot or mildew, and bugs don't like it. And it's nicer to work with (less itchy).