I cannot confirm the Firebird icon. My database backend is MySQL(JDBC), (actually Mariadb). I prefer to continue for the time being with the OpenSUSE packages delivered with my Linux Leap 15.4.
Editing views with external databases won't work. It's the same behavior for every other connection with MySQL/MariaDB, also with PostgreSQL.
So: Create queries, save it as a query, create a view of this query. For changing a view: Edit the query you have saved. Delete the view. Create the view from the query again.