Ask HN: How do you block distracting websites on your work device?

I have the bad habit of running into small roadblocks while working, and impulsively opening a new tab to some distraction (Twitter, CNBC, Twitch, etc). I'd like to set up my work computer so that it prevents this behavior, and generally limits the websites available on my machine to work relevant ones.

I travel around with my computer, so I want the "blocking configuration" to be on device (no router level changes). I exclusively work in Google Chrome. I have used the Chrome extension Blocksite [1] which works very well. However, Blocksite has greatly limited the capabilities of the free version (can only block up to 5 URLs) which annoys me. I also have some privacy concerns around using unvetted, third-party Chrome extensions for this task. I am considering building my own Chrome extension that has the same functionality, but I want to make sure I am not missing good existing alternatives.

[1] https://chrome.google.com/webstore/detail/blocksite-stay-focused-co/eiimnmioipafcokbfikbljfdeojpcgbh?hl=en