Totally feel this. I once found an entire site built with nothing but MySQL timestamp. I switched everything over to DATETIME, but since I did it in a straightforward way, I kept worrying there were hidden bugs lurking. In the end I just closed the laptop and thought, “whatever happens, happens.”
If all new software now starts using 64bit then presumably in 13 years time it's only a long tail of never been updated software that is an actual problem