I know nothing of the autoelectromagicinary that would be involved but the FG steering wheel already has 2 paddles;
Mode & Cruise.
Reconnect cruise to the lower rightside unused steering wheel button.
Use the
ICC instead of mode.
Speak to someone who has already attempted or considered what is required for the up and down shift signals and make use of the paddles already there.
If the paddles aren't big enough for you... make them bigger.
No easy job I'd think but if you nail it right you'll have plenty of friends for sure.
Otherwise I'd consider an extended straight shifter similar to v8supercars over your original suggestion.
Good luck 👍