Qt5 Settings in Linux Mint 21.2 doesn't work for Strawberry anymore because Strawberry is built with Qt 6. See this in the wiki:
I tried to compile the qt6ct utility mentioned there, but my version of Mint did not meet the required dependencies. But I'm a relative newbie to Linux so maybe I missed something.
I don't think there is currently a version of Strawberry available with Qt 5.