In your libmysqlclient21 example everything seems to be working correctly so I don't understand why you post that.
- you are eligible for 8.0.29-0ubuntu0.22.04.3
- you force downgrade to 8.0.29-0ubuntu0.22.04.2
- you upgrade once again to 8.0.29-0ubuntu0.22.04.3
- no higher version available in final dist-upgrade run
In your libmysqlclient21 example everything seems to be working correctly so I don't understand why you post that.
- you are eligible for 8.0.29- 0ubuntu0. 22.04.3 0ubuntu0. 22.04.2 0ubuntu0. 22.04.3
- you force downgrade to 8.0.29-
- you upgrade once again to 8.0.29-
- no higher version available in final dist-upgrade run