Welcome! Whether you stick with dressage or not, the chance to ride a new discipline can only improve your riding. I hope you enjoy it.
You might enjoy The Athletic Development of the Dressage Horse: Manege Patterns by Charles de Kunffy. It’s been one of my favorite books, and I suggest it particularly because I think the discussion of using patterns dovetails nicely with coming from a H/J background.
Dressage trainers, like any discipline, do come in many flavors. If the first one you try doesn’t feel ‘right’ to you, it may be that it’s the trainer rather than the discipline.
Some teach that the horse should be very heavy in the bridle, but this is not at all necessary or desirable.
Also look around for clinics in your area where you can audit.
USDF consists of many local Group Member Organizations that tend to put on shows, clinics, etc. If you find the one for your area, it’s possible you’ll find a website with a calendar and trainer listings that may be of help to you.
One of the things I enjoy most about dressage is the ability to compete against myself, allowing me to measure my progress without necessarily having to travel so much or so often (unless of course I wish to).
Good luck!