First of all: Awesome idea, totally underrated mod! For me playing on a 1440p monitor, the difference is pretty noticeable, especially for splitters.

There is a giant downside though: Loading times. Event though I got this game on a very recent M.2, with these large textures, it takes a very long time to load. Maybe there is a way to compress the textures, without loosing too much detail?

The sprites are already compressed.

There are options in the game that can help you with this, start your game, hold ctrl+alt and click on Settings, this should open the hidden options menu called "The rest", open it up. Search for "cache", it should show you 4 options, enable "cache-sprite-atlas". This should reduce the startup time after your first load.

Alternatively go into */Factorio/config/ open config.ini and enable the option there.