Why isn't there support for all versions of the game yet, including "Chronicles"?

strange, to say the least, reasoning - just take it and do it, it's idiotic to do everything from scratch when there's essentially a ready-made version that just needs to be slightly modified...

That's the thing, there isn't a "basically ready-made version." I wrote about this to you, and Sav and MoP (very strong and experienced modders) did on the df2 forum.
And it's not at all "slightly" modifying.
If it were that simple, it would have already been done. You clearly have absolutely no idea how it's structured/works.
An HD mod is thousands of patches and hooks installed at specific addresses in the SoD code. Each hook can have references to other addresses in the SoD code.
For each chronicle release (!), these addresses need to be found again. The structures, order, and size of the structure fields may be changed in the chronicles.
Moreover. A very large number of bugs in the HD mod have been fixed thanks to feedback from a large audience - this is hundreds of thousands of players. I estimate the audience for the HD mod for the chronicles to be in the tens, at best in the hundreds, well, okay, in the thousands of players. A lot of bugs (and they will inevitably appear) will be found and fixed very slowly.

In my estimation, an HD mod for the chronicles is a project that will take months or years. Even if you were to convert HD mod + SoD into the chronicles, which is easier and faster than making an HD mod for the chronicles. It's a very large amount of work! And most importantly, it's completely uninteresting! And, frankly, not very much in demand.
Just finding the motivation for such work is already a huge problem. Personally, I would be motivated by $90-140k with a down payment of $45-70k. Just whining and begging won't motivate me 100%.

that's why I was curious - why didn't you even try to do it and just limited yourself, roughly speaking, to one part...

In short: because a) it's difficult. b) it's not interesting. c) it's not very much in demand. d) it's pointless.
Why it's pointless has already been written. To undertake such a large project just to enjoy the menus, cutscenes, and portraits of Tarnum is absurd.
SoD (and its mods) is a GAME that, thanks to the random map generator and online play, has infinite replayability.
The Chronicles are not a game; they are just 8 campaigns with a few missions (maps). And the quality of these campaigns is debatable.
For SoD, an incalculable number of custom maps and campaigns have already been created.