CRT white balance is not stable

Hello, I got a Sony Trinitron KV-21CL10B for retro gaming (EU-PAL mostly). I noticed that the white balance changes according to the image on the screen and colors are off according to the prevalent color on screen.

Let's say I'm playing Super Mario 64 and there's lot of grass in the the screen, everything looks green-ish, if I move where water/sky is in sight everything looks blue-ish, same if red colors are prevalent on screen.
I also have a 2nd TV where colors are perfect and the issue happens with all systems I plug to TV, also with signals coming from the TV tuner.

Is there any affordable way to fix it? Sony Trinitron are supposed to be the best systems to run games on, it's a pity to send it for recycling.