> In all likelihood this will never happen in a particular timezone.

You sure about that?

https://lists.iana.org/hyperkitty/list/[email protected]/...

2026b - changes to future timestamps

2026a - changes to past and future timestamps

2025c - changes to past timestamps

2025b - changes to past timestamps

2025a - changes to future timestamps

2024b - changes to past timestamps

2024a - changes to future timestamps

2023d - changes to past and future timestamps

2023c - changes that changed future timestamps reverted

2023b - changes to future timestamps

I definitely prefer the... fragile? approach for this problem