Need help finding an app that helps me focus

Need help finding a FREE app that helps block apps that are distracting (instagram, discord, and etc.) ever since my winter break started i’ve done nothing productive.

And kept scrolling on my phone :( and i’ve been having horrible brain fog and intrusive thoughts (due to messing up my sleep schedule as well) and I have a week before my second semester starts (i take nursing as a course).

And I really wanna get back into focusing more and have good discipline..any good apps that are free and actually block other apps?

I also use an iPho