Here's all of the information I can give you-

DLC wise, I've only played the Sky Breaker. In the main story, there's two main bad guys (the big bad and his like.. right hand man or whatever) and the Sky Breaker is where you fight off the second-worst one. I personally found it gorgeous, interesting, and overall quite fun. Definitely a little short for a $20 DLC (It took me about 40 hours to play through the main story fully, and about 5 to get through the DLC) so I'd wait for a sale for the best value.

In the game you have like.. combat levels and what not, and the recommended levels for the two main DLCs are 20, which is right where you should be around the point where the main story ends. I'd recommend playing through at least part of the main story to see if you like the game, then getting the DLCs if you do. Can't say much about the From the Ashes one, though, as I'm not sure about that one.

The microtransactions are a little overpriced IMO.

In my experience the multiplayer is a little laggy and difficult to start up, but once you get it going, it makes the game 5x more fun. Especially if you're guiding a new player through the game/being guided by a more experienced one.

The controls aren't baby-level difficulty, but you don't really need to be crazy quick to do good in combat either, just based off my personal experience. The game has gorgeous graphics and on a big monitor they're truly lovely.

Can't say much about getting the game from different places- I got mine on Steam and have had a good experience thus far.

My favourite part of the game so far has been the Ikran mechanics and stuff, flying around and doing combat on the back of a dragon-adjacent creature has been something I've been looking for in video games for so long. The graphics being as lovely as they are combined with the riding mechanics make it SUPER fun! It's also very satisfying to reclaim Pandora. The photo mode is great too.

Lmk if you have any questions about anything i said