For me it fixed one thing, the mini mode in recent apps now works (home up plugin, good lock). Thats the only thing i noticed so far.

Try it and you will see

a54 would probably have a better battery life and the cameras are not that different, the s23fe just has an extra telephoto lens. There are some benifits for s23fe, like longer software support for it.

real

I recorded a 50 minute video on my s23u considering they are simmilar hardware you should be able to record until you run out of storage.

Why do you care if the camera is good? Buy a proper camera if you want to take good photos. S23U goes toe to toe with the iPhone 15pro/pro max and, in my opinion, gets beaten by the pixel 8 pro. So its one of the best you can get if you dont mind waiting for january the s24u will have a even better camera.

S9 will run genshin at max settings just fine

Nobody needed to know that.

You probably used it while charging and the cable just loosened, try using a different cable, if its not a cable problem then you might have damaged the port if you used it while charging. Maybe you user a faulty cable

Get a old/used xiaomi or any other Chinese brand phone. Preferably you wanna search for phones that fell in price not the ones that originally cost 100£ that way you get the most value for your money.

No, dont try doing that. Reasons: software is only compatible with the camera the phone came with, the connector could be different, and the chipset would likeley not support a better camera and you would have a hard time fitting a different size camera in the phone.

Technically possible but very hard to achieve.