Yes, you’ve got some problems…but likely solvable with patience and the right stuff. Do your best to NOT BREAK any more bolts.
Get yourself some type of good rust penetrating spray. I think Kroil is the best…but you likely will need to order on line. Readily available is PB Blaster and/or...
Don’t use an powered impact for what you describe. Get a proper fitting screwdriver as stated, try to get an JIS… super helpful in this situation.
in the meantime, use the closest fitting you can scrounge and hit the screwdriver with a large hammer while attempting to turn it. Control it…hit...