Demetrius and Steve are giving you excellent advice so pay close attention to their thoughts.
I do photography as a hobby, by profession I am a marketing prof and I do quality and risk management consulting, so I will come at this a bit from the business side.
The "best" equipment for you as a business isn't going to be the least or most expensive but people starting a new business almost always greatly underestimate the cost of getting started. The camera body MAY be the single most expensive piece of gear you buy getting started but the lenses you will need to do the type of multiple venue work you propose will, as a group, quickly add up to more than the body. Then think accessories including lighting and light modifiers, tripods, etc.
Then for the business side, you will need to consider setting this up to offer protection to your other assets so think LLC or similar with its setup costs. You will need insurance and business use of your car and/or home will impact those policies. Even with social media you will likely have some promotional costs.
How you price your services is another "deal maker or deal breaker" and this is one reason you really need to understand all of the costs/expenses you are incurring so you don't underestimate what you need to charge to fairly quickly get your new business from breakeven into providing some return.
As to camera platforms, I still prefer the DSLR because of the way that I do photography. I have no love for electronic viewfinders and most of my time is spent on the sidelines of field sports where I keep both eyes open and seeing an EVF with one eye and true real time with the other isn't pleasant. I use Canon 1DX III bodies which are expensive BUT I do this as a hobby and I likely would use something less expensive if I were doing this as a business. In my case, if I felt like I needed more income I charge many times per hour for consulting what I could make from photography so I don't worry about the cost but if this were a profit making concern I would do things much differently.
Finally, realize that once you start doing photography as a business you will look at it very differently because now you have to think about it as a business and not just fun. I also restore vintage amateur radio gear as a hobby and many times I have turned down people who have wanted to hire me to do restoration work. I have done free work for a couple of museums and also for some senior citizens but if I started doing this for business, the fun would quickly go away and what is now challenging would instead become frustrating.
I spent many years doing high level consulting work and I liked what I did, I loved the challenge, but only on rare occasion would I have called it fun. It basically was a way to ensure that I could retire at 55 and never have to worry about income but for the most part it was work. I would want to put a lot of thought into it before trying to turn a fun part of life into a workable business venture.
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
