Building out wall for electric panel

I am replacing a tiny 6 circuit subpabel in my detached garage with a larger panel and have been trying to find some info on this but haven’t been able to locate anything in NEC or other threads. My plan is to add some thick furring strips (2×4 on edge) or scab some 2x8s to the current 2×4 framing, mount the panel "flush" and then drywall around the new 2×8 "pop out" for the box, kind of getting the best of flush and surface mount.

Is this code compliant?

This would solve a few issues for me:

• the weird 12" stud spacing there so most modern panels don’t fit,
• provide around 7" of "stud" to give more room to run the feeders, which were brought in via a 2" pvc pipe by the original installer/electrician since I am having trouble finding anything to reduce that down to a managable size within a 2×4 wall
• allow me to keep several existing NM circuits that are behind the drywall andrun those through the top of the box behind the drywall
  *Finally, I could use EMT straight out the side of the box for new outlets ran with THHN.

Any references to NEC you guys know of that allow/prohibit anything about this or something obvious I am overlooking with this idea? I am good on the building code and framing part, just can’t find anything in NEC to make me think it’s either permitted or allowed.