The funny thing is that it actually works fine for me on their mobile app, which is the same app this post talks about with the poor data usage.
It just seems to be on my PC. It's only on the store. Even download speeds seem okay. But regardless of whether I use the client, Brave, Chrome, Firefox, Edge, they all are slow for the store page. Even things like the community pages and workshop all load fine. It makes zero sense to me why things like pictures/videos in their store load insanely slow for me, yet the images in things like the workshop have zero problem.
I've been trying to figure out what is wrong for quite some time and haven't figured out what could be causing it.
Have you moved to a different locality since you've had a steam account?
Steam -> Settings -> Download -> Region
I'm assuming you've already looked into F12 › Network tab? No requests getting stuck on DNS resolution of some weird CDN or anything like that?