If a user provides a time of 11/7/2021 1:50 AM America/New_York, how does the library determine if it's a -5 or -4 offset given that's when daylight savings time ends? I believe that's the ambiguity GP is referring to.
I'm trying to align time across a few systems I work with. One provides a GMT time with an offset (clean and useful), another system reports timezones and local time, and yet another system has no idea when it moves between time zones, but reports time based on a single timezone consistently.
Not dealing with multiple timezones in the past, it reminds me of Tom Scott's video on handling time and timezones, summarized at the end as roughly "Go find someone who built a library for handling times, thank them profusely, use their open source code, give them credit, and never worry about it again."