Option 1: Strip mine the company. This is more of the traditional PE/activist play. Once you stop spending all those R&D dollars, then Intel could extract a lot of profits from the x86 over the next decade or so. But this is only a short-medium term play. All mines run out of gold eventually.
Option 2: Split the Fab and design (x86) business. I'm not sure this helps that much, I think x86 is F'ed even if it could use the TSMC fabs. This is what AMD is already doing. The major important players (Apple, Amazon, MS, Goog) want to go ARM and then maybe RISC-V for their own strategic reasons anyway.
Option 3: Spend unheard of amounts of money to try and win back a process advantage over TSMC. This would entail spending tens of billions of dollars to basically make a bet that might pay off. It would be fun to watch, but success is not guaranteed, or even likely.
Is there an option 4?