can you install some playstore Apps, or does really any app install fail? (that’d be up to FRP then)
AppLounge 2.13.14 received internal library upgrades (current gplayapi from aurora) and fixes how the auth request is made. I’d wait for v3.2 and recheck. AL with a dedicated g-account should always work then.
One bottleneck is the token dispenser that can be exhausted from too many users on anonymous mode. But atm the auth seems broken in general, so wait for v3.2