I don't know about Razer recently, but I have a 13 button Logitech mouse (G700s) and it would be essentially useless without the Logitech software to configure it. I assume Razer mice are the same, you could technically use them without Synapse, but if you're doing that you may as well have bought a Microsoft Intellimouse instead.
Personal mouse experience, I had two Razers that died right outside warranty, while my Logitech is at >6 years. Those were before their driver shenanigans, but the drivers aren't even the main reason I wouldn't switch back.
I'm not sure if this is true for the G700s, but many other Logitech mice store the configuration on the device itself, which lets you configure it once and then get rid of the software or use it on computers or OSes where you've never installed the software. This is true for my G502.
It's true for a single configuration, but not if you want to bind different keys per program with the "Automatic Game Detection" mode.
I mainly use one profile for games and set any keybinds I need in each one, but I've used automatic game detection for other software like repurposing the DPI adjustment buttons for quick shortcuts to blender's popup radial menus.
Ah, gotcha. The G502 stores something like 5 modes and has a mode switcher button on the mouse, but I could see the convenience of wanting automatic switching per program.
I plugged my G700s into a Windows machine with the Logitech bloatware suite installed, programmed it, and I've been using it on a Mac for years since then without any trouble
I have a razer deathadder chroma with a kvm switch on mac/windows/linux systems. I do not have razer app installed on any of the three systems and the mouse works fine (including the forward/back side buttons and pressable scroll (so 5 buttons total)).
I recommend anyone with Synapse use your firewall to block all of their services from interacting with the Internet. I noticed Synapse was consuming a lot of CPU/network. I'm definitely never going to buy a Razer mouse again, I'll probably get a Zowie.
And Synapse did require a login for several years. Looks like it doesn't anymore, thankfully: https://www.tomshardware.com/news/razer-synapse-3-removes-lo...
Personal mouse experience, I had two Razers that died right outside warranty, while my Logitech is at >6 years. Those were before their driver shenanigans, but the drivers aren't even the main reason I wouldn't switch back.