We had similar issues with the Mindstorms Android app last year. From memory it was something to do with a change in how the apps needed to be packaged for the newer Android versions.
I reached out to Lego and got no where with it, they basically said that Mindstorms were end of life and implied it wouldn't be fixed.
After some searching I ended up recommending Mindstorms Makecode to our teachers. I havn't had much feedback, so unsure how successful they were with it in the end but it seemed to work when I tested it.
I found that I had to use the beta version of the site that contained several bug fixes for the Bluetooth connection. I also had to firmware update our Mindstorms to a newer version which was fairly straight forward.
https://makecode.mindstorms.com/beta