We've known that Apple has moved onto 5nm for a while now.
AMD securing more 7nm capacity has little to do with overcoming chip shortages.
The chip shortages are caused by insufficient supply of ABF substrates (which was caused by the pandemic and automotive industries mainly).
Without ABF substrates, TSMC cannot make new chips for AMD (no matter how much 7nm capacity they have at their disposal)... and this also applies for everyone else (Samsung, etc.).
Also, 7nm capacity was never an issue for AMD.
It was reported that TSMC always had enough capacity to meet AMD's needs (in the past, AMD underestimated the demand for its 7nm chips), but more recently, the insufficient supply of ABF substrates caused industry-wide chip shortages.
However, AMD DID recently agree to acquire Xilinx later this year.
Xilinx actually produce their own Integrated circuits... and one of the main reasons they agreed to this deal was to help AMD get more wins in the data-center space (where big money is), and I suspect that if they can do that, then its quite likely they will might also be able to supply TSMC with ABF substrates to for the entire AMD line of CPU's and GPU's.