A nice chapter, and it is indeed soul crushing that the manga is ending in 1 more chapter.

But it was a good run...
I remember reading some details about the next part of the story and can someone refresh me to why neither anime or manga will continue when it sounds more promising than the "intro" parts we got so far. The bits with
Euphie slowly losing her humanity and trying to keep it as best as she can, Anis almost dying and becoming something more than a human afterwards and the reaction of neighbouring countries to the two of them. Honestly, all of them sounds very interesting, so to just end everything here with this seems bizarre to me.
I'll try to explain, but I believe the big issue is rooted in the 12-episode batches modern anime is ordered in, and the struggle to pace stories around that.
First, credit where credit is due, the MagiRevo anime is a great LN adaption (especially given the constraints). Not just because of the story, but also how self-contained it is. It doesn't suddenly stop before we get any payoff like most adaptions have to. And the payoff scene we get with Anis and Euphy is incredible.
BUT that scene was at the end of book 3. And the end to this arc is actually book 4, which covers the time between Euphy making the contract and being crowned. This is actually one of my favorite books, but they already had to remove chunks of 3 to make the 12 episode count, so including 4 was impossible.
This puts the anime in a situation where a season 2 has to make the final part of the last arc feel like the start of a new arc (which isn't impossible actually). Then pivot to book 5 which is a transitional book between major arcs. And then either end on book 5 (probably the best choice) or adapt just the start of the next arc (which could be awkward). If anime could go back to 24 episode seasons, they could do all of the above and more.
But 12 episode batches just don't pace well with a lot of light novels. It would take multiple cours to get to the parts in your spoiler.
Also Diomedéa is one of the smaller animation studios, probably why MagiRevo still doesn't have a dub despite it's success. So their resources are more limited.
Now why does this affect the manga? Basically because the manga is following the anime's lead. It would take over a decade for the manga to adapt all 13+ light novels at it's current pace, and Pierro has already moved onto their next work. So they probably figured "if this end point worked for the anime, it'll work for the manga".