I did this on my 2019 Convertible and used Kona Blue touch-up for the forward gears and Red Caliper paint for reverse..........let it dry about 10 minutes and wipe off excess with lighter fluid on a Q-Tip........looked OK but I hated that knob and got a Ford Performance one eventually!!
You could use slightly thinned enamel paint, it will level out nicely. use a fine brush and "pour" it in the valley with the brush point. Testors, Tamiya, Model Master, all work well. Or even decanted Rustoleum. Work carefully and clean.
Or sharpie markers if the indent is white to start.