Some features of the site (like responding to your comment) require JS, but I just tried blocking JS with uBlock and I was able to use most of the site perfectly fine.
I am not sure about strict mode on Tor, but you should totally report back if it works. Give it a shot!
Well, regardless what tech stack makes it possible, when my phone data is throttled to ~55kbps Piefed is perfectly usable and most sites are not.