Try to uninstall the app and install it from scratch. I do have a pair of "legacy" Razer devices (Naga Chroma and Tartarus), both "works" (I have to unplug them and plug them back in for the app to identify the hardware and go past a "Please connect a Razer device" message/apply the custom key bindings). I'm currently running their 1.88 code (although 1.87 is the latest Synapse 2.0 you can download from the website, it does update itself after installed). Still, you might be better looking at replacement hardware: Razer drivers are pretty ancient, not updated since Mojave and already showing messages from Apple about them going to get broken on future updates since Catalina came out last year. Which is sad; I do enjoy having a ton of extra buttons for macros.