I made a similar site to Tuchu a while ago that attaches the highlights to the pdf: https://anishthite.github.io/ailight/ https://anishthite.github.io/ailight/.

I made a similar site to Tuchu a while ago that attaches the highlights to the pdf: https://anishthite.github.io/ailight/ https://anishthite.github.io/ailight/. It's a bit slow though, I've been trying to get it to run faster.