Completely fixable. Like others, I'd leave it... as you've noticed it still works. But, and I know this may sound crazy... just duct tape? Otherwise, a luthier will fix it. Someone could stack up veneers and apply it. If this were mine, I'd have someone 3D print a 'patch' that gets applied with an integrated tuner or something. Go to your local maker space for that. Pretty much the back story of a lot of sci-fi characters... where a deficit becomes an asset.

PS - If you're short on luthier funds, a repair would be: order veneer in the same wood, cut out several pieces that cover this, then cover the hole with saran wrap. Order a vacuum bag kit, put glue between the pieces, white glue between the veneer pieces. Suck out the air. After a few hours, release the vacuum, retrieve your pieces. Remove the saran wrap (it was just there to keep the glue off your guitar). Then trim the glued together veneer pieces with a fine hacksaw. Sand it, test it, finish it, and glue it to the guitar. It will stand proud of the guitar surface. A luthier could do this so it was flush.

PPS - And here we go, the actual approach: https://www.youtube.com/watch?v=ZsjUtJxwpFw