Without seeing your flow so I can see what issue you are having the answer is not really.
In the end, I think you did a decent job of explaining it but (and its probably just me), what I would want to see it
PersonA Comes in to Flow, in France its 2:00 PM (sorry I said PM lol), but Outlook thinks its 1:00 and bla bla.
We have to deal with Daylight savings time also in the US so we have a very similar situation, but I have yet to see it be a problem for anyone.
So I just want to make sure I solve the real issue, meaning if we fix the startingTime issue would that fix your problem or are you asking how to fix timezone issues, and then I would literally need information like
1. Is any of this regional? Ever
2. Do you deal with other countries and care about that
3. Do you have a .... daylight savings type setting in France? for Outlook?
4. The months that are +x versus ones that are +y so if we really do need to do time conversions we have to know what month it is.
I haven't honestly had a French regional ask like this before so trying to verify it as I would daylight savings time here in the US