This is a known and long standing issue.
The foundry access token is valid for one hour, it can not be extended. The refresh token is valid longer (I think 30 days).
However, Tableau only recently added support for „single use refresh token“ that foundry uses. I assume it will take some time until the foundry connector is adopted. After that, Tableau should be able to properly use the refresh token to prevent frequent re-logins.