Is there a keyboard out there that connects to my S7, my wife’s Ipad and iphone AND crucially has a built in trackpad that works. I can find a logitech one with some nifty device switching but it doesn’t have a trackpad.

Do trackpads work with iPads and iPhones? They don’t have a cursor to track.

I think the android should work with any usb keyboard/trackpad as long as the phone supports OTG.
I’ve just plugged a usb keyboard into my OnePlus3 (via an OTG adapter) and it worked perfectly…. a trackpad simulates a mouse so that should work also.
I suspect your issue is getting something to work with a iPhone – but then IANAFB.

Good point – I kind of assumed they would replicate the swiping though?

Stuff like this

Works fine with Android, it claims IOS support, but I don’t own any IOS nonsense.

Android devices should work with no dramas.. Plug in a mouse or I assume a trackpad and you get a mouse pointer appear.
No idea if this is possible with apple stuff.

J

iOS isn’t designed for a cursor. It’ll work fine with a keyboard though – I use an Anker Bluetooth one that USB charges. £16 from Amazon, and it’s got a really nice feel to it, easy to touch type and the key motion is similar if not better than my HP laptop