You think you could use yarn?
I've seen some people run a slicker brush through strands of yarn many times to loosen the fibers up. From there, they make many tassels and attach them to make a tail, fit for a wolf or other large fluffy-tailed creature. The results look pretty softer, in contrast to this one pictured which looks a bit more like plastic (unless that's the kind of look you're looking for).

I've seen yarn tails before, but I'm skeptical of their durability. The individual fibers in those sorts of acrylic yarns are pretty darn fragile. These fibers are thick enough that I'd trust them to take a bit of a beating.
But you're right, the texture of this material is maybe not ideal. I'll see how it ends up once it's trimmed. I'm willing to trade a bit of aesthetics for resilience, but maybe I'll give yarn a try.

As a yarn tail crafter, I cannot recommend brushed yarn for this particular type of project.
Now, I am not saying yarn tails are not durable and that they can't last many years if properly cared for. I know one of my earliest attempts is still out there 5 years later and it gets near daily wear and even goes outside and camping.
However
1) They simply do not last forever. You have to brush them when they start to get matted up and this will eventually lead to them losing body over time.
2) if these dragon tails drag that's a huge no. Dragging brushed yarn results in a lot of matting and is something I never recommend.
3) a chainmaille dragon tail will (hypothetically) last forever: as mentioned above brushed yarn slowly loses body. It would end up looking really silly to have a tiny tuft at the end of a beautiful chain tail. Or eventually nothing.

However, what I /can/ recommend is the "fancy yarn" I use for my bushy tails and draggers. You can click through my gallery to see examples, I don't like directly linking my products on another artists work unless asked. But those types of yarns are a lot less prone to matting, don't require being brushed out, don't tend to lose body over time except maybe a stray bit at the den here and there, are even washable, and would probably give you a variety of different effects to try out and go for, since they come in a variety of types.

Hope this is helpful to you.

Thank you for your expertise! I do tend to favor longer tails, and so while I don't plan for tails to drag, with the poof they might. And yeah, I don't really like the idea of these tails needing regular maintenance care. I want them to be idiot-proof.

The bushy tails in your gallery are interesting. I'm not sure it's quite the sort of look I'm trying for, but it's something I'll keep in mind.

i have been making yarn tails for about 7 years or so.. if this does not drag id say go yarn. its easy to shape and cut.. mine have lasted forever. mine also do not lose the yarn being brushed hardly at all.

i have someone who has got a few from me and uses them all the time. they look as new as the day she got them.

iv had a dog get one of mine.. brushed it out looks as new as the day it was made.. so they.. well mine anyways are very durable

iv never had anyone say theirs broke in any way at all. and i have sold so many of them.

i also put in the extra steps to make them nice and shine.

but yeah if they dont drag id say yarn.. if they do i cant help ya on that one sadly.. if you want more info IM me.. i dont talk about what i do with my tails out in the open:P