There was K9 Web Protection but it was ended in 2019 by Symantec. It was perfect because after setting up password you had to wait one week to unblock it back again :)

You can try LeechBlock. It works as plugin in all browsers.

First thirty seconds are the worst for will :)

So it is better to ask a relative/friend/parent/spouse to set up a password for you - then you cannot unblock the sites back again without them.