Any apps that offer free German learning?

hi I actually paused from self-studying German a year ago, but I can't say I've reached beyond A2 level. and since it has been a while, I have gone a bit rusty. since I also do not want to rely on duolingo (especially with the AI controversy), can anyone suggest another free app that can help me?

I would also appreciate it if anyone can send me free PDF to support my learning.