Help needed on projector and screen choices

H everyone, new guy here. I am in the process of building out my home theatre, this is the first time I am doing anything like this so I need some unbiased direction. I have a beautiful home, and going to make a legit theatre to match. It will be 14x21 ft , no light penetration at all, doing 2 rows of seating.
I have done a lot of reading on buildout of the room itself so I think I have that pretty squared away.
As for the projector and screen(and audio) but I will keep it to a projector and screen in this thread, I have gone to a couple dealers, they seem to both point towards a runco, of course cost accelerates very rapidly. I am completely open to other brands, but I have started at runco to learn more. In their price range of 5-15k I see ones with LED, dlp, lumens, contrast etc... Ones released years ago cost more than ones recently released and so on. One of the newer ones has an led that only puts out 540 lumens, that seems awfully low. I want to do this project right, want something that we will all be more than pleased to sit and watch. Also what other components will I need. I was thinking the 2.35.1 as well for the screen.
All help is welcome, thank you so much in advance, your help is appreciated!

Thank you for the reply. Where do I find the planning service? And where do they recommend to by equipment? Buy through them or do they give u locations to buy from?
Thank you!