The rings of power was a mess because the estate were so hard to work with. They could only use notes or something like that instead of the actual stories.Perhaps it will be tested in court, but in recent years the Tolkien Estate and other family members have raised no objections to JRR's work appearing in various forms. After the out of court settlement over the original Peter Jackson trilogy there were no further objections to The Hobbit trilogy. The Rings of Power was an amicable agreement, and one of Tolkien's grandsons, Simon Tolkien, worked as a consultant on the series. The LotR musical is currently appearing in various countries (coming to Plymouth next year - go see it, it's excellent). The Bag End exterior location set in New Zealand is an authorised 'location based experience'. I think the Tolkien Estate are way more relaxed about JRR's work these days, and if they get a cut of the rights money from Universal I think that's morally correct (given that JRR Tolkien originally sold the rights for peanuts), even if not strictly necessary in law.
Having seen the artwork published yesterday and the endless commentary on it, the only thing that really excites me is the possibility of a LotR land. If they come up with something which resembles Majid Sarmast's concept art for Universal from a few year's back I'm going to be super happy.
If theme park rights are owned by a different entity this should be different, but Amazon were hamstrung massively from the beginning and they paid billions for sweet FA. That’s why certain characters or areas were and will never be included in the TV show.
They could work off notes and notes only.