Help for primary body for fledgling photography business

I have a photography side hustle that I’m hoping to evolve into a business. I’m currently shooting family, newborn, and maternity portraits on my R8. I have the rf 50 1.8 and the rf 28-70 2.8 stm lenses. As I’m taking more clients and charging money, it’s making me nervous to have only one camera body with a single card slot. I really love my R8 and how light and portable it is, but I’m thinking it would be a great backup body, or second body, if I get something else. I was thinking perhaps the r6 mark ii, especially since prices are good now the mark iii is out, but I didn’t know if it made sense to get the latest and greatest and go straight to the mark iii.
Any advice?