I don’t have much advice on finding the caps, or what will fit on it, but the profile that Keychron sells on their low profile boards is LSA (and appears to be their own profile). Using the profile name should give you a bit better search results, but it looks like there isn’t much out there that will fit those low profile switches.
Do you really need video?
My monitors have multiple inputs, so I just use a USB switch for my mouse and keyboard, and then switch the monitors between devices as needed.