Commentary screen reder does not support keyboard commands. How can I contact the developer? I am planning for a year subscription still this is the only thing preventing me from completing the licence purchase.
use the help section to find a suitable contact method for yourself. Either join the telegram group, or send an email. There's even a whatsapp group out there.
I believe there's an option to turn on something to make it so that you can sort of interact with the arrow keys, but as far as I know there's no official keyboard support. Honestly I'm one of the very few people that have gone back to Talkback for various reasons and only check into the CSR group from time to time.