Edit: Just noticed you are directly setting x on tick, if you want to disable that as well set your MoveForward variable to 0 then reset it after the delay
Sure, no problem. Set the default value to 0, then just drag your variable out and do set (enter whatever value you want for your speed) and connect it after after the delay like this:
There should be a check mark under the up/down arrows.
Also, I just noticed a mistake in that last BP. The player controller should be plugged into the player controller pin (not target) on the enable input node