On my Palm Pilot there was a “floating” time zone that behaved like this. But I can’t find this feature in any modern app. Outlook doesn’t have it either.
Apple's calendar has it on macOS, but not on iOS... (it's annoying how mobile everything always has to be so neutered)
And yet iOS calendar is also more powerful in that you can set different time zones on the start and end of a single event, which macOS calendar will show but not let you edit.