There is currently no option available to not disable the touchpad while typing. This has been reported earlier and was marked "not a bug" because one could edit the configuration file without using gnome-control-center. However, under Wayland, there is currently no way to change this setting as the Wayland version of libinput (for a reason I can't understand) does not have a config file. The default behavior, which disables the touchpad while most keys (except for a few modifiers like Shift, Ctrl, etc.) are pressed (and, it would seem, for a short time after) makes most gaming impossible. For instance, in a shooter game, you could not look around while also moving with WASD.