@IvanOV-104
Hello there, I coincidentally started a x2.5 scale RSS career recently. QSRSS is outdated and the Rescale! mod wasn't working for me either so I just ended up re-scaling it myself manually.
It was a pain to get working with the visual effects and editing all of the various config files from the latest release of RSS to scale it down by a factor of four wasn't fun but I did eventually get it to a satisfactory state for a playthrough. There may still be some oddities with some of the planets/moons terrain meshes as I didn't have time to spend hours finely tweaking each one but it's overall pretty solid in my opinion.
Here is a link to download the required portions of my GameData folder, just copy it into a fresh install of the game. Confirmed working in version 1.7.1 but Kopernicus should be the only mod that is version locked so if you have a different game version going forward then that should be the only mod you need to change out.
[Download link removed by moderator. Please don't share out your actual GameData folder, due to licensing concerns. We realize you're just trying to be helpful, and we're sorry to have to remove the link. Log files are okay to share, and it's great to list which versions of which mods you have installed, but please don't share the actual contents of GameData. Thank you for your understanding.]
Hope this helps you,
Mojibake