Honda stripped bolt on blade

Hello, I have a question and I tried searching but I didn't see an answer

I have the Honda HRR2165vxa, one of the bolts that attaches the blade to the blade holder will not come off. I tried heating the bolt, using liquid wrench, using the Irwin bolt extractors and that gator grip but it will not budge. All of this has basically chomped the bolt down to a round nub. I'm thinking that the only thing left is grinding it off and hoping that whats left of the bolt will come out with a pair of vice grips. If it still will not come out my question is can I just detach the blade holder from that center bolt and look to replace that part or will that part not come out unless both bolts that attach the blade to the holder are out?

Thank you for any replies, I can't believe this bolt is giving me the problems it is.

Try a big hammer with punch and or chisel striking it left as if you were loosening bolt, wear safety glasses & gloves.

This may be difficult but perhaps you tried squirting upwards with the liquid wrench . The stuff works bestl if it can sit in contact with the corrosion which is probably holding the bolt. If you can take out the deck (is there one?) and turn it upside so you can pool the liquid wrench around the bolt interface for 24 hrs. While you are waiting in this manner strike the bolt nubbin lightly with a soft hammer (copper or lead) or lightly with a steel one every couple hours. Tap it around the dia and when the session is done replace the little pool of liquid wrench. Then use the hammer/chisel in counterclockwise blows on the outside circumference of the bolt stub. Repeat, Do the anti -corrosion dance and good luck. Maybe you can then grab it with a vice grip.

Blades tend to self tighten.
Usually if you gring the head off and drop the blade you can take them out with you fingers

Yes the center bolt is the only thing holding the blade adapter on.

Here's some illustrations and a few steps that might help.