Hi. I have responses posted in multiple threads. So... in as much as a change in the time server "seemed' to fix my tablet, my desktop (like you - in the same place) decided to have time zone issues after a Windows update. Changing the time server on it is not working along with the other usual suggestions.
A recent response on another time zone thread read as follows (a bit much for me though):
Take a look in the Recent Activity page in the Security section of your Microsoft account to see which type of IP address is being used to identify your login location for each device.
My bet is that since Microsoft had enabled the ability for their servers to support the newer IPv6 addressing sometime last year, that more and more individual computers, especially those supporting the newer drivers and technologies provided with Windows 11, are likely ending up with IPv6 addresses, leading to those being used by devices for the first time in many cases.
What this means is that though the old IPv4 addresses have been around forever and the locations associated with them have been adjusted at least to some extent long ago, in many cases the new IPv6 addresses have been used far less often and so in some cases may not yet contain valid location information.
Since that information is the responsibly of both Regional Internet Registries and for the morre3 detailed location information, the Internet Service Providers, this isn't something that Microsoft itself has any control over. Though people have become accustomed to quite accurate information relating to their personal smartphones, they forget that these actually contain a geolocation device using the GPS satellite location services, while at worst they can typically be roughly located using the cell phone tower(s) they're using, while the typically PC or tablet doesn't usually have these abilities and is more often located using its IP address.
Here's an article discussing these issues relating to IPv6 and Geolocation.
Understanding IPv6 Geolocation: Challenges and Tools
So if you determine your device is being attached to Microsoft servers using IPv6, it's most likely IPv6 involved and even if this isn't true, it's still highly likely it's your ISP or other network provider that's responsible for the inaccurate location information, since that's not something that Microsoft would handle other than for its own server or other internet facing network locations it's directly responsible for.
Rob