My primary device is 6.5 inch screen. I only mention this, as scale goes it doesn't seem to bad, but I often find myself fat fingering the wrong button often.
Hence the suggestion of hotkeys. Basically an option for full keyboard over keyboard and mouse.
If you do decide to branch off you may have more real eastate, there is a lot of extra space on my phone. But my is not 16:9 either.
But this is also only a small solution. I'm not sure the more common platform for your game. But would a small QoL update.