Both my mouse and keyboard are logitech and I love them, despite how terrible their software is in both stability and usability. The only reason I put up with the terrible software is because I only had to interact with it the one time to set up my color scheme and mouse dpi. Just trying to get the software to install to do that was terrible and that's what they want people to subscribe for, sounds dead on arrival to me.
If you want to get rid of their software, for the RGB part you can use OpenRGB instead. It runs on both Linux and Windows and can do pretty much any RGB controller (RAM, GPU, mainboard, mouse, keyboard, ...).
They both sound pretty good options. I looked real quick but didn't see an answer but do either of them allow you to save to the onboard memory of Logitech devices or does it only work with them running in the background?