Chrome just nixed the 4chanX extension, and it's perma-dead. Is there anything comparable to return similar 4chan browsing functionality (downloading pics, refreshing expired threads to desuarchive, etc.?

Is that Chrome desktop?
I'll be damned if some browser is going to tell me what extensions I can or cannot run.
You can load anything in Developer Mode from a local folder in your system (that's how you test your extension while working on it).
Read more here: https://www.reddit.com/r/chrome_extensions/comments/zh4ave/how_to_manually_add_extension_to_chrome_when_i/

That should keep it installed until you manually remove it.
If you get any annoying popups about your debug mode extension: https://stackoverflow.com/a/61572593

>>1534838 (OP)
https://www.firefox.com/en-US/thanks/

>>1534838 (OP)
>chromium user
Install it as a userscript. Instructions are on the website.

>>1534838 (OP)
Use tampermonkey and install 4chanX manually.