One comment is that the slowest page to load was the Gallery [0] as it loads an ungodly amount of PNG files from what appears to be a single IP (a GCP Compute instance?)
I see 421 requests and 150 Mb loaded. As it seems to be mostly thumbnails, have you considered using jpegs instead of pngs, potentially use lazy loading (i.e. not load images outside of the viewport) and potentially use GCP's (or another provider) CDN offering?
Once I clicked a thumbnail, loading the article itself (for example [1]) was quite breezy.
The gallery is a great showcase of what your site does -- I think that it'd be worth making it snappier :-)
Cheers and congrats again
P.S. Also, the paper linked below [1] seems to have a few conversion problems -- I see "EQUATION (1): Not extracted; please refer to original document", and also some (formula? Greek?) characters that seem out of place after the words "and the next token is generated by sampling"
[0] https://papertohtml.org/gallery
[1] https://papertohtml.org/paper?id=02f033482b8045c687316ef81ba...