We use extension version 2.2.3 on M2.4.1 and find that your extension has a problem calculating the taxes
When we change provinces it doesn't even recalculate the taxes
The root of the issue is that the tax is not updated on the site when the region_id changes but not trigger ajax call.
We have fixed this issue and modified this file
Please apply the attachment and flush the cache on site.
If you need any further support, please feel free to contact us.
We'd like to help.