This combo does work for me on Windows 10 (I.e. Qt for Android v5.15.2 + Creator v7) - but on LINUX (i.e. Ubuntu 20.04) it fails! Compilation succeeds, but deployment crashes Creator.
I tried the Creator v8 beta, to see if that new version fixed this but that didn't work either...
So... I installed Creator v5.0.3 along side my regular Qt installation (with Creator v7), and that worked! You can get it here: https://download.qt.io/official_releases/qtcreator/5.0/5.0.3/
Note: Qt went totally nuts in the last year, pumping out one major
version of Creator after another for some crazy reason. They were only on v4 after 25+ years and
then they dumped 4 new major versions on us in like 1 year!! What the
hell is the story with that?! Anyway, I think Creator v5 is the safest
bet for Qt v5.x. For Qt6, you probably want to be on the latest and
greatest Creator version (whatever happens to be at the time you're
reading this!).