problem with synchronized arrows

i got a huge problem conserning stepmania or in the groove
each time i play im getting more great than marvellous for no reason
on my screen it appears to be right but when i press i get randoms great or perfect
ive been playing for like 10 years difficulty 18 and i know how to play verry well any kind of song without having a single great but right now when i changed my screen and my desktop pc it appears i cant play without losing
i tryed to fix the resolution or refresh rate but nothing work what should i do ?
i really tryed everything in the setting folder named metric.ini
is it my new monitor the problem ?

There are two things it could be, global offset, or visual delay. If the monitor is the only thing that changed, it's probably the visual delay.

1. Use the Calibrate Audio Sync option to set your global offset.
Do this until hitting perfectly on beat with the sound results in a marvellous. It will automatically adjust your global offset until you're hitting on the beat and getting marvellous.
2. Adjust the Visual Delay using the debug menu by holding F3 and tapping Y or U.
Do this until the arrows are exactly on the targets when you hit them and get marvellous.