Orbi RBS350 Antenna Radiation Patterns

Would be all 360 degree pattern from each unit. 

Good luck finding documentation on the RBR350 product.  The FCC provides a list of every product that Netgear has submitted for approval since 2001: https://fccid.io/PY3 

I did not open every submission, but I never found one for the 350 product.

Netgear definitely publishes radiation patterns for some commercial products. (I have seen patterns for some ceiling mounted WiFi access points, such as the WAC540.)  Do not remember ever coming across radiation patterns for residential products.

FURRYe38 is correct that the radiation pattern will be similar to a typical "vertical dipole".  Since I could not find the FCC submission for the RBR350, here is an internal picture of an earlier Orbi router:

Notice the two combination 2.4G/5G antennas mounted approximately vertically.  This will result in a roughly donut shaped radiation pattern, with the lowest radiation directly above and directly below the unit.  If you open the RBR350 or RBS350 case, my bet is that the antennas will look very similar.