This app was created for OnePlus 7 Pro, when a11 was released for this phone a disturbing scaling issue was introduced. The only way to fix it is by locking the refresh rate to 90hz

Practically it has 2 buttons that execute 2 different adb shell commands:
adb shell settings put global oneplus_screen_refresh_rate 0 or 1

Additionally it can and help other One Plus s lock their screen refresh rate to MAX using 'Lock to MAX' option.

Open source project, you can find the code in the following repo:
https://github.com/llabropoulos/refreshRateChanger