Hans Grohe makes a diverter that is wall mounted, but $$$. I would opt for a solidly mounted diverter rather than have one on a stick or attached to the breakable shower arm pipe.
This is pricey, too, but I think it is what you are looking for https://www.homedepot.com/p/Symmons...hrome-Valve-Not-Included-S-4504-TRM/205991813
This is pricey, too, but I think it is what you are looking for https://www.homedepot.com/p/Symmons...hrome-Valve-Not-Included-S-4504-TRM/205991813