Which Orbi Mesh Router will separate 2.4 Ghz and 5 Ghz with RBS20's

I currently have a RBR40 with 2 RBS20's.  It's been a nightmare setting up camera's, doorbells, light switches because the RBR40 will not separate between 2.4 & 5Ghz.  I've had to remove the RBS20's ...