Broken screws in bed

This isn’t too related to Tacoma’s but kinda. Trying to install utility rails on my 07 but 2 screws head broke off and are rusted in there. I’ve tried some screw remover tools but they don’t seem to be working wondering if anyone has suggestions. Looks like previous owner tried to get it out as well but was unsuccessful

 

Small nut on top, weld to screw, [unhook battery, GOOD clamp to ground IF screw is in steel, if not, life sucks] remove screw when cools slightly. If you can't grab it well, try to dremel a slot in the top of it carefully. If you can hold the nut in the ground clamp and hold the nut to the screw, you can try to weld it also. A wing nut can give you a bit more surface for the ground clamp to grab.

 

From the photo, looks like there is a divot nearly centered. Be a prime candidate for a reverse bit and an EZ-out.