It’s not the only thing that leaks timezone data, and the fix is identical: have the machine pretend you’re in UTC.
For example: if you enable Resist Fingerprinting (RFP) in Librewolf, it will lie to websites and pretend your timezone is UTC - because of course timezone is one of the factors used to fingerprint you - and all the sites you visit that show you your local time, or depend on your local time for something or other, will show you the wrong time. And that’s how you know it works 🙂
Sure it is. There’s a button labeled “Manage exceptions” that does exactly that.