Bad screen resolution permanently crashes Poco F1

In short: I used SecondScreen app and changed the screen resolution to a bad one. The app autostarts and changes my resolution automatically. This causes a boot loop. What can I do? In detail: This is what I did on my non-rooted Poco F1: 1. installed Second Screen 2. I gave it the permissions it needed, using ADB via my PC, and other permissions it asked via UI . 3. I chose some big resolution. 4. I shut down the PC, before disconnecting the phone from PC. 5. The phone was stuck in the weird resolution, so I restarted it. 6. it is now in an infinite boot loop. :( It starts booting normally, but than the screen resolution becomes bad (see the photo), and, before finishing the booting, it restarts again :( At last, the recovery menu is reached and it gives me 3 options. 1. Reboot (this is the restarting loop that brings me back to the same menu) 2. Access via MI PC Suite: I cannot access the device this way; the device is not detected. It never sees the device, except in Fastboot it says: "Try connect in normal mode first then switch", but I cannot enter "normal" mode. 3. Wipe the data (if at all possible, I would prefer to avoid losing the data). What I know: Codename: beryllium Bootloader: locked Anti version: 1 I can get my phone into FASTBOOT and adb sideload modes, but unfortunately not in the "normal" adb mode. Can I uninstall the app somehow, stop it from autostart, undo its damage, or anything to fix the phone without losing the data? A non boot-loop fix was done by typing: From adb shell, type: wm size reset wm density reset but I cannot find out how to do that from FASTBOOT or sideload....