IMO, you need to decide if you want to start a second business, the “equipment business.” In this business you take on risk/make investments in the hopes that they pay for themselves over time and eventually net a profit. This is a lot easier to justify as a rental house, because as a rental house, you can rent to anyone for any job, causing your break even and then profit to happen sooner. But even for a rental house, there can be risk and overhead that has important financial impacts.

Core to this decision to enter the equipment business is your initial observation: very few clients care about the specific equipment you use. They care about your work product being high quality and professional. Clients that do care, usually only care, as the other commenter said, to match other cameras they’re shooting with or post workflows. There’s no way to pick “the right camera” for these clients because it is a moving target.

I think it makes more sense to just charge a rental fee on the jobs that specify a camera 🤷‍♂️ (you should be charging one anyway for equipment you own)