According to reports, Apple is set to shift from 5 nm to 3 nm nodes between M2 and M3 SoCs. TSMC should have its N3 node ready in time for the A17 Bionic too, both tipped for releases in 2023.
https://www.notebookcheck.net/Leak-outlines-the-Apple-SoCs-set-to-rely-on-TSMC-s-N3-node.582691.0.html