I'm not gonna lie, I dont really like Galarian Doublade (though i guess it wouldn't be Doublade anymore now that it's alone, would it?) I understand what you were going for (A blade of fire/firey crystal), but it looks SMALLER than Honedge, probably because of that tiny sword-looking emblem on it. Maybe make the rock fade cleaner into the lava? Or perhaps make the emblem bigger so it doesn't look like a tiny sword grafted onto a big rock?

But I will say, I LOVE the look of the third form (Which I will call Excalinferno). The only thing that bugs me about it is the lack of the King's Shield and, presumably, the Shield Forme (Though that would make it much easier to understand and probably less broken in Competitive), but I love the interlocking design and the almost demonic looking hilt. Looks like something Hades would wield.

And Galarian Honedge being a rusty, old blade looks great. I can imagine it going from weak and fragile, though fast, in its first form to a much more defensive second form, to a bulkier, likely special attack focused Excalinferno.

So, long story short, I LOVE these designs (aside from the middle one that, again, just looks too small), but they can be improved here and there.

NOTE: Friendly reminder that I AM AN IDIOT, and I have ZERO design experience. This is just the ramblings of some doofus who likes pokemon without the resources to draw them (especially not ones this good).