Not sure if you’ve intentionally omitted it but I would also include YouTube in this list. YouTube can be very addictive with all the clickbait thumbnails etc.
Yeah I did conciously omit it actually, but only because I consider Youtube to be basic internet infrastructure and quite valuable if used right.
However, for me personally, I've actually blocked Youtube from Chrome when not in incognito mode to keep me signed out by default and I've also completely blocked the site from my iPad (and ofc I also don't have the app installed).
I unfortunately struggle with some form of social media addiction and I've made pretty dramatic changes to keep myself away from these sites.
you don't have to release the extension, you just load it unpackaged by developer mode in the extensions settings