@jonas Thank you for the answer. I'll wait for the new version, as I think other Debian Bookworm users (yes, MX is based on Bookworm) will also have problems compiling the plugin. That's the only downside to Debian - it's stable, but some packages are older (cargo-c is version 0.29 on Ubuntu, 0.14 on Debian).
But I'm very happy that the plugin can otherwise simply be turned off (with Clementine it got stuck in the login when Spotify no longer supported the plugin). Strawberry is otherwise really great, I'll stick with it. Thanks!