spotx - well, I tried, but honestly, I don’t need one more app especially when everything works in the browser. Plus, I prefer portable setups and there’s no portable version of spotx, so, it’s pretty useless for me.
It’s explicitly said on the Spowlo GitHub page that they use YouTube for downloading, so, there’s no way to get 320 kbps tracks or flacs. Instead, I’d recommend to try some Qobuz/Deezer-based solutions, there are quite a few of them there. Or use slavart or something like this, or good old soulseek, there’s even an Android client for it.