Host files not working when editing it via Nano but works when using SelfControl?

So I'm trying to edit my host files using sudo nano /etc/hosts so it can block some sites, but while I can edit and save it, no website is blocked. Here's a real head scratcher: when I block the same sites using https://selfcontrolapp.com/ , everything works. It's not the content of the file or the formatting - while SelfControl was running/working, I literally copied/pasted the modified Host File on Terminal and used it as my new Host file (I pasted it and everything is identical). Does anyone know what's going on? I've flushed the cache, did sudo chflags noschg /etc/hosts, changed 0.0.0.0 to 127.0.0.1, but nothing seems to work. I suspected it might be caused by https://github.com/2ndalpha/gasmask or https://switchhosts.vercel.app/ , but I already uninstalled them.