Is my Razer mouse incompatible with my Razer laptop? Bought same day.

Some years ago, I purchased my Razer Blade Stealth laptop directly from Razer, along with a Razer Atheris mouse.
The laptop uses Razer Synapse 2. The laptop is not supported by Razer Synapse 3.
The Atheris mouse, apparently, uses Razer Synapse 3. The mouse is not supported by Razer Synapse 2.
So my native instance of Razer Synapse does not recognize my Razer brand mouse.
I am denied a significant amount of my Razer Atheris mouse's functionality and its capacity for customization. My only means of configuring the mouse is through the Windows 10 control panel, which has limited functionality already. But in my case the Windows mouse settings do not even recognize that my mouse has five buttons. For example.
Windows 10 is running up-to-date Razer drivers for the Atheris mouse (driver ver. 10.0.15063.0).
I have tried installing Razer Synapse 3, but it will not run concurrently with Razer Synapse 2.
If Razer Synapse 3 runs on its own, it successfully recognizes the mouse, as expected. But if I shut down Razer Synapse 2 in order to run Razer Synapse 3, I lose control of, for example, my Chroma keyboard lighting, because Razer Synapse 3 does not support (i.e. recognize) the Razer Blade Stealth or its keyboard.
I have also tried a couple of freeware, 3rd-party mouse control/customization applications that came recommended on other message boards, but I found them to be shabby and gross -- clunky interfaces, spotty functionality, weird glitches. They sucked. And this shouldn't even be a problem in the first place.
Do I wish I knew that, despite their X-TREME product design, their Wachowski branding, and their snappy copy, Razer was actually just some shabby little foreign outfit with bad tech support and good web design before I bought a bunch of their products? Yes. I have some regrets about the man I was then. But this just isn't fair -- I bought a Razer mouse along with my Razer computer, and as a reward for my... I don't know, brand loyalty? Or something? Is that Razer makes them essentially incompatible with one another. It's...pretty frustrating. I've looked, I think, hard enough--using popular search engines and my own, non-idiot brain--for a solution to this and I haven't found the right answer.
So I will send off this impotent cry into the message board void to be misread repeatedly, or ignored entirely, or answered ineffectively, disdainfully, or in bad faith. Apparently it's the only means of recourse Razer is offering me ("No warranty? Sorry, FUCK you. Go ask the internet you MONSTER" was Razer's official response)
If there's any justice in this world, there is a solution to this problem that doesn't suck and doesn't cost me any money, and I would very much appreciate any assistance or insight you can offer, whoever you are. I do not understand why you would hang out just waiting to help people on the message board of basically the Surge Cola of computers but I'm glad you're out there. Thanks!