If you need to reset a forgotten PIN, please connect your device in bootloader mode:
In order to do that, swipe your finger across the screen while simultaneously plugging the cable into your Trezor Model T, or if you have Trezor One, connect it while using your index and middle finger to hold down both buttons.
After the device is connected in bootloader mode you should see the following screen:
Click on the green gear button to open the device settings.
Before proceeding with a factory reset, make sure that you have your recovery seed and passphrase (if enabled).
As long as you have verified your recovery seed you can proceed with the factory reset, which will erase everything on your device including the firmware.
Tick both boxes in the next pop-up window and confirm the action directly on your device.
After this procedure your device will return to factory settings.
You can reconnect it and go to Trezor Suite, install the firmware and recover your wallet and set up a new PIN.
The process can be also seen in this video: