Should be plenty fast.
I’ve only used one option myself. An app called TouchOSC on Android (Seen it on both Google Play and Amazon). I’m pretty sure there are variants of it for the Apple realm as well. This one is designed to work over a network and does require either a USB to MIDI DIN interface, some sort of UDP/TCP interface over the LAN/WAN, or an OSC server/client on your PC. There might be some simpler ways than going OSC (the way I use it), and there are loads of MIDI controller apps are out there to research.
The trick is to get the events from the tablet into Cubase in CC form since it doesn’t have native OSC server/client abilities. Some of the apps I looked at require an actual USB to DIN MIDI interface hooked to the tablet. Others can do it over LAN or wireless WAN. There might be one out there that can use a network rtp protocol. In that case you could run rtpMIDI to get a connection over your WAN/LAN.
Personally, I use TouchOSC and run an instance of Bidule in stand alone mode (free demo should work for this) to serve as the OSC server/client, and use loopMIDI to get the events into Cubase.
So, my physical MIDI controllers are routed into Bidule, I’ve built some bidules to convert OSC messages into CC messages Cubase and its hosted instruments can understand. I route Bidule out to a loopMIDI virtual port, and then set my inputs in Cubase to use the virtual port.
I’ve also got a few Generic Remote maps running in Cubase in order to control more of the DAW from the tablet.