Some vice grips saved me in a similar situation. Half rounded off bolt head, used VG to get a good grip on it, then made a hillbilly breaker bar type setup that got me extra leverage on the VG handles and that got it to break loose.
Hammer and flat wrench is worth your next try. If the right sized wrench fits a little loose now, then you’ll need to get a tool that you can try to flatten out the sides that are rounded
Good luck let us know how it goes
Oh my gooooooddddd, I feel like a giant moron now that I know what the AA button + Reader View actually do. Thanks everyone. Happy that y’all learrrrrnd me it 👌