PS2 Game Discs Not Reading on YPbPr Video Output

I recently took my PS2 Slim (90001 model) to a repair shop because the laser was failing. They fixed and returned it, but the games still wouldn't read and I was having trouble displaying it on my TV, so I took it back. They replaced the laser again and were also having trouble having it display, but they were able to make it work using a xyab AV to HDMI adapter. I took the PS2 back to my place and tried an xyab adapter myself, and it technically works, but the video quality is very poor. I realized that my game discs now read successfully when setting the PS2 video output to RGB, but they don't read when I set it to YPbPr (the PS2 still displays on the TV, it just stays on the home screen and doesn't read the game discs). I need the YPbPr output to work because I recently bought a RetroTink 5x to get better video quality, and it doesn't work on RGB output.