HDMI (Nebula Max) to USB-C (Galaxy S5e tablet)

Using a new Anker HDMI to USB-C that works perfect with my Galaxy S10 and Nebula Max, also between my tablet and Samsung TV, so I’ve proved the cable, tablet and phone… But for some reason I get very inconsistent link between my Nebula Max and Tablet S5e. I’ve been trying for days to find a reason. I also get no sound when using the tablet out of the Nebula, occasionally it will come on for a few seconds.
Not sure what else to do, it seems like it may be that they are just not compatible.
Could really do with some help as I’ve bought this projector to run while camping and planned on running everything through the tablet.