I have been working on this and other things for churches for over 40 years. Just buy what you need. It is readily available.
1. You have given 0 relevant information on what you need. Pictures don't help this.
You need to know how many people are on the worship team, and how many are going to be on the elevated platform. Will there be more than one level? I have seen as many as five tiers for really big choirs, but you can even do more. Is this who the elevated area is for? Once you know that it is easy. You call it a "room," but I don't really think it is a room.
2. People have been making tiered stage elevation platforms for the last two centuries, at the very least. They improve with time. Today's are excellent. Buy some. They are exactly what you need and they come in every height, width, and depth you can imagine. If you need tiers you stack them. They will even make them custom. Don't recreate. Use existing equipment that is readily available or you will eventually pay more. If you ever move you can take them with you. Oh, and they fold flat if you ever want to remove them for special occasions. You really do not need detail drawings of these. Floor plans are good enough for the company that makes them. Call them.
I did a search for "stage platforms for singers"
Here is only one of the many websites that popped up: https://www.stagedrop.com/portable-staging?pi=2
Just because you can draw something doesn't mean you need to. Just go buy what you need. I have been working with church people for way too long. They are notorious for wanting what isn't real. You need to educate them on what they need or you will spend all your time running in circles. The other thing they are notorious for is unethical bid shopping. They do not know it is unethical. You need to educate them.
Oh, one more thing. These things are beefy and strong. You could probably park a car on the big ones!
Gary