PSA Long OP: Cost of starting my own gym question/s

So I’ve been recently considering the idea of starting my own gym. I’m probably a couple years or more away of being financially able to swing something like that but it’s something I’ve always wanted to do. I’d probably finance the entire thing myself. I don’t want a partner (aside from my wife.... maybe)

Anyway, I’ve got some training experience. I’ve coached CrossFit for a little while and I ran our company’s PT during my time in the military. I also spent some time with some units that had very experimental and rigorous styles of training. Been training in various ways since I was about 16 years old.

Anyway, I’d like to get an idea as to what the financial situation might look like in order to start my own operation. Ideally, I’d like to have a metal building built. Something about the size a lot of baws build to store their toys. Maybe 1500-1800 sqft. On a concrete slab

I don’t want it to be a CrossFit gym. I don’t really care to pay those affiliate fees and I don’t really like a lot of their training methods. I'd like to run a boot camp style operation (similar to CrossFit but safer movements) there’s no need for soccer moms to be snatching weight... But I won’t get all that.

Anyway, boot camp style regiment and do classes the way CrossFit owners do it; a couple classes in the morning before my day job and a couple classes after work. I’m in a pretty rural area so probably wouldn’t have a huge client base but that’s whatever. My wife and I both train daily. She also played soccer in college and coaches some kids in a youth league, so she’d be using it to train too. We’d definitely use it as our daily training facility and would save us $100 a month in gym fees, plus I feel like I’d be able to use the gym as a tax write-off (although I am a little green in that process) but financially justifying it is easy if I know what my overall cost will look like.

Like I said earlier; 1500-1800 sqft metal building on a concrete slab. I’d like to have those garage style roll-top doors a lot of boxes have.

1200 pounds worth of bumpers. Various sizes. I’d buy these cheap. No sense in overspending on bumpers.

I basically want it to be able to support; Bench, Dead, Squat, Push-Press, pull-ups, and have enough room for general boot camp style stuff.

Not a huge operation by any means. I’ll probably eventually add a rogue rig in the middle but I want to start small. Maybe train some local high school/college athletes and some soccer moms, or anyone interested in a military-style training program.

I know it might be a stretch, but has anyone here built their own gym or done something similar to this? Got any advice?