2 way switch wiring questions

I haven’t used it myself, but if I understand it use case correctly, this device handler should do what you’re asking for (using two master switches in a 3-way setup).

https://community.smartthings.com/t/beta-z-wave-tweaker/81558

What I do have in my house is a smart master and smart 3-way switch. However, the 3-way that I have is only a powered z-wave switch with no load or traveler (just line and neutral). It functions as a 3-way by having a z-wave association with the master switch (established through an auxiliary switch device handler in ST). I didn’t see why this association couldn’t be made between any z-wave devices, and came across the device handler you see above.

You might at least try it out if you can get the master switches cheaper.