I use Burnout Buddy, it can block both apps and websites, you can set up custom rules, time based, usage based or triggered by Shortcuts (for instance I have one set up to block Reddit when I enter the gym).

Just want to say I was looking for something like this the other day that didn’t feature an obscene subscription and I’m very glad you made me aware of this app. It’s lovely and free!

Woah this is nice! And pretty generous free app