Not Earning XP

[Cass]

Since launch, I have been experiencing the issue that I only get XP from a few random Leader Challenges, even though I have completed many others from those leaders.
I can't get any of my leaders higher than lvl 2, and I even bought the Founder's Edition.
I also don't get any XP from Foundation Challenges Milestones, which are the most important ones to level up your account and unlock mementos.
I'm missing many Mementos because of this, and am almost quitting the game.
My account is stuck at lvl 11, even though I should certainly be 25+ from so many playthroughs.
I sent a bug report to the official channels, but still haven't had an answer on how to fix this.

When I played on my account on my friend's PC, I earned XP as normal, but when I came back to mine, the issue still persisted.

Already tried to uninstall and reinstall the game and it didn't solve the problem.

[Harthy]

Know how to resolve?