How to solve brightness problem after screen replacement?

Hello,

I bought an unoriginal screen to replace my broken screen on my Xiaomi MI A1.

I did the replacement but as it's not an original screen, there is a problem with brightness :

When I boot the phone, the Xiaomi logo appear with a normal brightness. But then, when the logo disappear and the home screen appear, the brightness become extremely low (can only be seen in a dark room).

Everything else works perfectly (touch, apps, ...).

Even if I move the brightness bar, the brightness doesn't change. I also tried to change it with apps but it didn't work either.

The weird thing to me is that the screen is able to have a good brightness (because when the phone boot the brightness is good) but when in use, the brightness is terrible.

So, is there a method to have a good brightness on an unoriginal screen after a replacement ?

Thank you !