How to block all websites containing certain strings on all browsers?

I've been trying to find something online but they all use the hosts file and seem to directly edit it with a script. This method I've found is pretty lackluster for this purpose since to effectively block a website, you need to find all of it's subdomains which can be a pretty long list, and for each website to block, the list gets pretty long. I was wondering if there is a way to get all subdomains of a certain website I want to block, but preferably, I'm looking for the ability to block all access to a certain site containing a certain keyword, ie any domain with the word 'test' would be blocked. What's the best way to do this? Browser specific extension are not what I'm looking for and I would preferably like to do this in Python, but any language is fine. I have a very limited understanding of how networks interact and function so this might not even be possible, please lmk if that's the case.