Great link!
https://spin.atomicobject.com/2016/07/06/time-zones-offsets/

"Given a local time and an offset, you can know UTC time, but you do not know which time zone you’re in (because multiple timezones have the same offset)."

So, given a time zone you can know the offset (Google it, for example)..
Then, given the time zone and the local time, you can know UTC.
If orgmode gets the UTC there is not ambiguity.

But, that would mean that the offset related to the different time zones must be downloaded and updated from some site.
As you said before, that offset can change. For example, peninsular Spain has the same time as Berlin, but as this doesn't make much sense, it could change, so updates would be necessary.
I have been thinking about how I would use this feature. So use cases appeared, which arose some doubts about how to use this feature, and an opinion for the Poll surged:

If I wanted to assist to a "Mastering Emacs book club" meeting in America/Vancouver, while living in Spain: Doubt: Should I use local time of America/Vancouver to schedule the meeting?. Like: [2024-02-04 12:00 @America/Vancouver] (I don't like space before the @, for the Poll).
1. Doubt: I suppose my agenda timestamp would be: [2024-02-04 do. 21:00]. (Spain local time). Correct?
2. If I went on vacation to Brasília, my agenda timestamp should change to: [2024-02-04 do. 17:00]. (Brasília local time).
   Doubt: How must the local time zone be updated to get that timestamp changed?
3. Back to Spain, I see that, for political reasons, Vancouver's winter time-zone changed from UTC-8 to UTC-9.
   Doubt: How would my tz database be updated?
   Doubt: After updating the tz database, my agenda timestamp would change automatically to  [2024-02-04 do. 22:00]. Correct?
4. For the Poll: What would be the expected behavior if we used the UTC offset?  [2024-02-04 12:00 @-08,America/Vancouver]
    - We should know beforehand the DST of Vancouver, or there would be warnings. It seems more difficult for the user: maybe the "-08," should be optional?
    - Case 3: After updating the tz database we would get warnings too. To correct those warnings, should the UTC offset be changed manually in the timestamp?. If there were 35 meetings in Vancouver throughout the year, to change all the UTC offsets could be non trivial for a normal user: UTC of the summer and winter would differ.
      [2024-09-04 12:00 @-07,America/Vancouver] should be changed to [2024-09-04 12:00 @-08,America/Vancouver]
      [2024-02-04 12:00 @-08,America/Vancouver] should be changed to [2024-02-04 12:00 @-09,America/Vancouver]