The list I use have a datetime column that has a default value set as Today() in the list setting in SharePoint online. So when an item is created, it saves the correct time - currently in British Summer time. I have a flow that sends an email picking that datetime value - when it sends, the time is sent an hour less than the stored value. I don't if its being sent as UTC or GMT, I guess both are same?
I have verified the site regional settings and Flow settings - both are correctly set with UK time. Am I missing something or is it a bug?