Intel literally outsourced their Arrow Lake manufacturing to TSMC because they couldn't fabricate the parts themselves - their 20A (2nm) process node never reached a production-ready state, and was eventually cancelled about a month ago.
Intel foundry screwed up so badly that Nokia's server division was almost shut down because of Intel Foundry's failure. (imagine being so bad at your job, that your clients go out of business) If Intel client side chose to use Foundry, there just wouldn't be any chips to sell.
Intel doesn't currently have nodes competitive with TSMC or excess capacity in their better processes.
They don't even have competitive capacity for all their CPU needs. They have negative spare capacity overall.