What are you planning on for a screen? I've thought about building something like this in my house, but it seems like people always run projectors to get the big screen, and I don't think it's worth putting all that money and effort into it to watch a projected image.
Now that a 77" OLED is under priced $5K though, a quality display in a huge format is becoming a reasonable option. Samsung has some 82" QLEDs out for around $2500. You can pick up a 2019 model of that 82" QLED for under $2k. They have 98" models now too, but those are $60,000 still. LOL.