Hi Arnoud,
I am not sure whether you see my other direct reply to OP, really sorry that message was intended as a direct question to you. I never realized that I did not reply directly to you till now.
The good news is that I managed to successfully install the Pi's ARM version of both the Wolfram Engine and the front-end Mathematica to with full GUI working with Termux-X11. Because this is my first time getting involved with the Wolfram Community, I am not sure how to share it as a tutorial. Do you know whether it is appropriate for me to make a tutorial for that on WC? If yes, where should I put that?
Kind regards,
Quan Le Thien