change device-model without root i want to change the device-modell of a non-rooted device.

is there ANY way to do it (that doesnt involve rooting)?

maybe also an app that sends that the device is compatible.
By device model do you mean Android version? In this case, it is possible without root, but you will be left with the company. Some companies offer Android upgrades (to the latest version) for devices. To attempt to get the latest version of Android:

Go to Settings > About > System updates > Check for update.

If it says "upgrading" or "updating" you might be in luck!

If not... there really isn't much else you can do. Unless you want to try root, a custom recovery, and flashing a new version of Android (besides voiding your warranty, this could hard-brick your device). Or contact the company and see if they offer Android upgrades for your device model.