Locally hosted parental controls/website blocking

[nya]

I am interested in playing around with porn blocking/computer user control, but most of the software I see for it is controlled over the internet and often sends things like browsing data reports back to the host servers. Which is something I'd like avoid. Is there a way to have things fully local, except possibly downloading updated blacklists, that is controlled by a password known only by my partner and/or that I can lock behind something like TellYouLater?