Therefore you will have to manually reboot the device by pressing the main button, the power button and the volume down button. As soon as the screen turns off, move your finger from the volume down button to the volume up button (while continuing to press on the other buttons) in order to enter into TWRP.
If so, I already tried that but again I got stuck on the loop… I’ll be trying to install magisk and the link that piero recommended with vbmeta, if still necessary with magisk