No there's only the switch to enable/disable instant replay.
CTRL+R is an OS hotkey (refresh webpage).
Left and right key combos are working for me (with the preset combos).
Ryzen 5 5600x, B550 aorus pro ac, Hyper 212 black, 2 x 16gb F4-3600c16dgtzn kit, NM790 2TB, Nitro+RX6900XT, RM850, Win.10 Pro., LC27G55T..