My Pixel 4a would also still be fine. If Google had not killed the battery. I think by now Google has asked (=paid) people to swap batteries on at least 3 different Pixel phones.
Good point. I think it would be fixable by using the Change Time instead of the Modify Time, because that changes when moving the copy over the original.
Step 1: discontinue the public repository, step 2: sell access to your GPL codebase.
The GPL (and even the AGPL) doesn't require you to make your modified source code publicly available (Debian explicitly considers licenses with this requirement non-free). The GPL only states you need to provide your customers with source code.
Sure, but it also allows your customers to modify the source code you provided, and distribute/sell it. With MIT they can simply relicence it and sell binary-only versions. The open-ness stops at that point.