Backup/Video Camera?

Hello!

I got hired on to go on tour with a band for photo and video work and looking to get back into filmmaking. I’m just having a difficult time deciding what camera to go with. I want something that can be a good backup/cinema quality camera.

I currently have a Sony A7III for photo and light video work, it’s done wonders since I first bought in back in 2018. But am wanting something slightly more top notch in terms of video specs. I’m wondering if I should get something like the FX3, a7IV or a7RV?

Should stay in the Sony ecosystem for lens compatibility or explore other options?

If anyone has any suggestions or input, i’d love to hear it!