2020 Ford Explorer ST
19mm bolt, I’ve tried with all my might to crack this off and so has my FIL who has worked on cars all his life.
Only thing I haven’t tried is getting the wrench seated and smacking it with a hammer… is that really the best way? Don’t want to round it off any more than I already have.
There is no room to fit a socket wrench up there.
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