The information provided in this bug report is not correct. The package just needs a rebuild. Nothing more.
Specifically, the particular build of Amarok that is currently in Sid (2.9.0-1) only depends on libmariadb18 because it is an old build. Rebuilding the package resolves the dependency issue. The source package depends on default-mysql-server-core which depends on mariadb-server-core-10.3. And somehow libmariadb19 came along for the ride when I installed Amarok's build dependencies on Buster. The package is building right now and this evening I will enjoy Amarok on Buster. I hope you all will too.
