No chance they get Apple
The TSMC/Apple relationship benefits those two companies far too much. TSMC benefits by having Apple prepay for supply years in advance which TSMC uses as funding to build out the new capacity with zero risk, and Apple benefits by having first access to the newest nodes with a guaranteed wafer supply, and with TSMC's process rollout schedule tailored to Apple's product cycle needs.
The interesting question for me is whether Intel would accept AMD as a customer, and whether AMD would be interested or would not trust Intel to treat them fairly when they are Intel's main competition. If Intel truly intends to operate as a foundry, it has to be a true "arm's length" relationship like Samsung's fabs are from their phone division.