Unusable scroll lag on galleries with thousands of images.

I recently moved a large gallery of mine to my FileRun installation and, for the most part, it worked fine.

However, the main part of the gallery, which consists of 5703 images and is continuing to grow, become highly unusable and has extreme lag spikes while scrolling. This is on a brand new dedicated server on the local network with 12 cores and 48GB of ram. The database is on the same machine as well.

I have already set up thumbnail caching with ImageMagick, FFmpeg, pngquant, and stl-thumb.

I do not mind if it takes a while to load initially, this is expected with having so many files, but the massive lag spikes while scrolling is unusable.

Is there a way to fix this does not involve moving the files to separate subfolders?