After installing brand new 4.4.1 instance with MYSQLI adapter the system check widget complains about lack of UTF8mb4 support. There is no such warning when PDO adapter is used.
No warnings. Presumably MYSQLI is equally supported.
Using official docker approach:
I also repeated the same clean install with RDS Aurora (mysql 5.7 compatibility), and observed the same problem.
You're right, the tooltip is misleading, the full system check indicates the same exact problem as seen in the issue you linked:
Can we merge this issue with the one you linked? EDIT: On a second thought, I think there is an important distinction. The problem I describe here manifests itself right away after a simple install, not by changing an existing database afterwards.