part of the point of having your own setup in a normal family room environment is you dont need all that ridiculous expensive stuff just to make it better than a theater. You dont need sound deadening, you dont have other loud ass theaters right next to your family room, if someone else in your house has shit blaring them tell them to turn it down, otherwise for a family of 2-4 its not even a problem unless you have neighbors who are constantly doing construction in which case you have other problems
Lighting, turn off your lights and just have dark enough shades to make the room black, you dont need theater lighting
Seats, just get the most comfortable couch you can, you dont need recliners and to replicate the experience when you have a couch that 3 people can fully lay down on comfortably, much rather have that than separate recliners.
Speakers, you dont need them mounted inside the ceiling, this is your own house. You can get 2 front facing towers and a center. Then either some speaker stands or wall/ceiling mounts/hangers for all the rears.
You most definitely can get a home theater experience that beats a movie theater in 3-5k easily. Your estimates and advice seem based on those that must have an entirely dedicated and replicated theater experience in a separate room of their house, but you really dont need all of that.