RBR 40

Not in the way you mean. No.

Explanation: Orbi routers can ONLY be a "router" (no matter what mode they are in, see below).  They can never be attached to another Orbi router and function as a "satellite".

Any Orbi router can be placed into "Access Point" (AP) mode and connected to any brand of router, including Netgear Orbi.  They then function as a stand-alone WiFi access point, the same as a $30 no-name unit from Amazon.  They will not be "integrated" into the Orbi system.  Devices will not "roam" from the original Orbi network to this router (or back).  It would be sort of a waste of an expensive piece of equipment.  However, if the choice is between letting it sit in a drawer unused and using it as an overpriced WiFi access point, some people find a good use for it someplace.

The other awkward part is that (as far as I know), an Orbi router cannot connect to other routers over WiFi.  It needs an ethernet cable.  This is less desirable than that $30 unit from Amazon.  BUT... suppose there is a Cat6 ethernet cable running to some part of the house where there are WiFi devices that never move.  Connect the Orbi router as an access point.  Give it some different WiFi name and put it on a channel that does not interfere with the Orbi.  Now, things that never move like garage door openers, IP security cameras, printers, etc. can have internet access.

Wow.  What a rant.  Sorry.