date and time zone issues

I have a powerapp which collects a date and time.  It is then submitted to a sharepoint list.  I have users in multiple time zones.   However I am finding that when the date is pushed to Sharepoint it adjusts to the local time of the sharepoint site, not the actual time that was entered in powerapps.

So for example if in powerapps I put 15:35  as the time, when it gets to sharepoint it comes in as 13.35 if the user was 2 hours ahead.     I  need the actualy 15.35 to show in Sharepoint.. How can I do this? I'm not sure if it's a powerapps or a sharepoint issue?  but I want to show exactly what's typed in powerapps with no adjustments.  Is this possible.

Thank you