Hi,
My answer is probably reaching you too late, but I would recommend this one, but only if you are like me : I mean always on the go, living in a small place and...more likely to spend money on software rather than hardware....
https://www.amazon.com/CME-Xkey-25-key-Bluetooth-Controller/dp/B01CRHQY1C
It's a really small USB keyboard which you can connect on your Mac or iPad. It is very flat and will follow you everywhere. But if you're a pianist or keyboard player you might consider a bigger one with responsive keys and so forth.
