Thank you for the hint, something a bit strange is that “power + volume down” did not work to force power down on my XA2.
I had to long-press “power + volume up” instead (info found in [Release notes] Pispala 5.1.0.11 - #35 by amaretzek), so for anyone having the same issue with the tutorial it may be useful to test both combinations (and also tapping the corners, although it didn’t work for me).