Depends what you're actually storing. There are plenty of cases where the timezone is not metadata; it defines how the datetime should be interpreted.
For example: your local mom and pop corner store's daily opening and closing times. Storing those in UTC is not correct because mom and pop don't open and close their store based on UTC time. They open and close it based on the local time zone.
Storing them in UTC is valid here also, but their IANA time zone string should also be stored ‘somewhere’.
When people go AWS, Azure, GCP,... other languages take the reigns.