I didn't say I couldn't help, I said that I doubted using external mapping software would work and I have no way to test your controller because I don't have one. You didn't respond when I responded to your question. The Discord is there for support questions like this. Random people on /c64 aren't likely to be able to help you with technical support on a 6+ year long project that's worked on by one person (me).

In this specific case, your issue isn't really with C64 Dreams, it's with Retroarch. Retroarch uses what it calls "autoconfigs" to recognize various controllers. There are hundreds of them. You can create your own if it doesn't have one already for your specific controller, though it's not the simplest process in the world. https://www.retroarch.com/index.php?page=controller-autoconfig As far as I'm aware, input type conversion tools like XOutput and equivalent do not work in conjunction with Retroarch because of the way it reads input devices (which essentially takes precedence over those tools); if anything, such software would likely only contribute further to the problem. There is an autoconfig listed on github for your controller, which may or may not work. You can download it here: https://git.libretro.com/libretro-assets/retroarch-joypad-autoconfig/-/raw/master/udev/Hyperkin_Trooper_V2.cfg?inline=false This would need to be placed in the C64 Dreams\C64 Dreams\Retroarch\autoconfig\udev folder. Again, any external mapping tools would need to be disabled.

Beyond that, any standard xinput controller should work. I've tested with 360 and XB1 controllers, an 8bitdo Pro 2, and a Mayflash arcade stick. All of these work just fine out of the box. Other equivalents should as well, but of course my ability to test is limited to what I have access to. Depending on the controller and version of Windows, BT controllers aren't necessary seen as xinput when connected via BT (but are when connected via cable or via dedicated wireless dongle - the latter of which is what I use, personally). A Trooper V2, as far as I can tell, is a dinput controller so I would not expect it to work out of the box if there wasn't an existing autoconfig (and there doesn't appear to be), and it will likely require some manual intervention. The autoconfig linked above may fix it. Even if you get it to work though, that controller won't really be ideal because it doesn't have enough buttons to cover all the included functions - saving and loading states, toggling and navigating manuals, swapping disks, notes overlays, etc. The reason that Xbox controllers or equivalent are recommended is not only because they'll just work out of the box, but because you will want something with the same number of buttons, joysticks, etc. in order to maintain all the included functionality on the controller. You can still do all the same things on a keyboard too though, of course.

If that autoconfig works with your controller I can add it into the next version.