I use a tower computer but I don't use a ssd for Renpy games. It would be the first time I need a ssd to run a Renpy game. BTW I just tested it on a ssd and strangely, the loading time is nearly the same. But it seems a little faster if I don't uncompress the .rpa.
In any case I also encounter some slowdowns in the game menu when the background image changes.
Main menu/config menu first load stutters are a known issue, it loads all the images from the image carousel into memory and since each chapter adds a few, it adds up. I've culled it a bit so it's no worse than chapter 5, but no better either.
Background images loading slow, well some scenes use QHD (2560x1440) sized images to allow me a greater zoom range, so that leans heavier on memory use, and I believe that after loading, ren'py holds the images it uses in memory in an uncompressed format, it might simply be that you're running out.
Since I layer several (sometimes many) images on top of each other for animation and parallax effect, it might be you notice it a lot more with LomL than other ren'py based games.
If your PC if reasonably spec'ed, consider checking if some other process running in the background isn't gobbling up a lot of RAM.