If the letter came with the Gemini then what good did it do? Mine did not come with a letter...
The point was that some posts earlier, I had asked for a written source to confirm that the claim that the x25 wouldn't have e-SIM wasn't just an unfounded rumor. Well, I had that written source myself, all along. Silly me.
Also, in that letter I got (read, and - apparently - forgot), they explained they presumed I preferred to get my Gemini earlier, rather than wait for them to sort out the e-SIM issues. Towards the end of the letter, they invited me to contact them, should I wish to discuss this further, because they want backer to love their Geminis.
Had I done so, and explained e-SIM was important to me (it could be, as three operators around here alread has launched some e-SIM support), I presume I had been given the option to return the Gemini and wait for one up-to-spec. Since, after giving it some thought, I don't think it matters enough to me, I haven't contacted them. Anyone for whom it does matter, do contact them and explain you do require e-SIM support.