If you've got the budget and the space for a workshop, just go for it, no doubt about it. It's honestly a solid investment, especially since you're constantly doing this stuff and even planning to make money off it. I'd suggest checking out some designs here https://www.uspatriotsteel.com/metal-workshops/. This company gets pretty good reviews overall, and I like that they've got a turnkey system with ready made building types and sizes.