you can use a bluetooth mouse or an USB OTG (adaptor from micro USB to “normal” USB) cable to connect a USB / bluetooth mouse to use the screen. bluetooth mouses require you to be able to pair them via the settings, so the screen has to be still partly responsive.
it is possible to fix water damage in some cases by using 99% alcohol (Isopropyl alcohol).
i have a problem with the display after i got the phone connected to some saltwater at the sea.
or videos on youtube.
the screen test gives this output.
i will try to clean it with alcohol tomorrow to see if it fixes it, but it would be nice if i could get a replacement unit. can you name a time when the new displays will arrive? otherwise i will have to get a replacement phone, which wouldnt be really in line with what fairphone wants us to achieve (use the least ressources as possible).