If the H has lost GPS, RTH will do nothing, neither can you use Smart mode to just pull back on the stick.
The first thing I would do in that case (or any loss of control) is to increase altitude.
Going higher can fix RC connection issues and will make GPS signal stronger. (by getting away from ground objects, buildings, walls etc)
It will also buy you time to locate the aircraft visually.
Hopefully you also pay attention to the telemetry before it went down to have some understanding of where your bird is facing, and without touching the yaw, bring it back by pushing on the position stick to make it fly closer to you. until you see. but this might be risky too, you might end up flying further away.
In new environments I always try to fly accompanied by someone who I designate as the spotter, their sole job is to be aware where the drone is so it's easier to locate in case of catastrophic failure.