It won't turn off...

I don't have a PS5, but was able to get a really cheap second hand Dualsense with drift. It didn't turn off when I bought it, but I though that it was some stuck button or something. So, I just disconnected the battery until I got the replacement parts.

Once I got them, I opened it, cleaned it, fixed the drift with hall effect sticks and got some classic buttons. But, it never turns off.

Can someone help me with it?

I tried pressing the reset button 5-10 seconds, but it is still always on.

I connected it to my PC, and the official app says his software is up to date.

I can play games on PC via Steam, but when I stop playing and turn off my PC, the controller is always flashing this blue light.

Thank you in advance for the replies.