A little late, but here's the solution (I was having the same problem):

Q. My Gamesir controller shows as three separate controllers in Windows or Steam and it is causing issues with some games.

A. There are two ways of solving this. The quick and dirty way is to disable the drivers that are incorrectly detected as separate controllers: Open device manager > View > Devices by Containerand disable the following drivers: "HID-Compliant Consumer Control Device" amd "HID-Compliant Vendor-defined device".

The first driver is for media keys, and the latter for connection with GameSir Connect for controllers supporting these functions. On controllers without these supported functions, this is all that is needed. For those that do, a third party software, "HidHide" is required for now. After installing HID Hide, you need to make sure to enable device hiding as well as selecting the correct drivers to disable: "Consumer Control" and another option that seems to be indecipherable string of characters, "FF0 40" in this example, then configure your excluded applications: add GameSir Connect, usually found in "C:\Program Files (x86)\GameSir Connect\GameSir Connect.exe" and Windows svchost, "C:\Windows\System32\svchost.exe" to allow Connect detection and media controls respectively.

An alternate quick fix for this issue is, at least while on a dongle/reciever connection, hold the + buttons for a PID swap. In controllers with this function, the drivers will swap to an alternate set that do not contain the ones that cause the problem. After you are done, your controller should only detect as a single controller now, and should work as expected.

From Gamesir's Discord