ROG Phone 2 bluetooth PS4 Controller issue

[Second_Grader]

my ps4 controller sometimes doesn't pair up with the bluetooth, keep on pairing while there is no progress. sometimes when it does paired, after i disconnect both and tried to connect them again it would just automatically disconnected. even after i managed to connect both i don't get any input. So basically it's like i didn't have a controller connected at all. Forgetting and/or disconnecting device while still connected also will results in an unending disconnecting process. While at this the only way to disconnect is turning off the bluetooth. kinda shame since i wanted to try a lot of games with the ps4 controller. is it just me? is it my phone or the controller?
thank you in advance

[WaitingKy]

android 9 isn't compatible with ds4 controller. just wait for android 10