Compatible GPU not available for Illustrator but works for PS

Hi Guys, I was bothered by a weird GPU bug for a longtime. My computer is Thinkpad P1 G4, with RTX A4000 on laptop. I used Illustrator from 2020, which works well until last year: it was shown that GPU not compatible. I have used all the method on web which I can find:

1 update NVIDA drive https://www.nvidia.com/download/index.aspx

2 change the graphic setting

3 delete the old preference file in adobe for starting

etc

but nothing changes. 

It is not problem of my GPU, as PS can detect it and use it smoothly. Nowdays, my illustrator is like running on a old machine, just due to GPU didn't work.

Any suggestion and help? Thank you very much! 

BTW my illustrator and PS are all updated. I also tried old version, never works. I exhausted now......