Congrats on the new pond, Sparky!
Most of the people on the forum use their liner-based ponds for fish or human recreation. Therefore, the liner is usually covered with earth materials to allow for plant growth (in a fishing pond) or beach sand (for a swimming pond).
Further, the material covering the liner serves as protection from the liner being punctured.
However, your sides in the background of the photo look too steep to hold material.
The usual solution is to design the pond with one shallow bank. However, that option is probably closed since the pond is full constructed. Is there a shallower slope in the foreground of the photo?
If so, you might ask your liner company what kind of material they typically put on top of the liners in your area?
If steep all around, then I think your idea for some type of mechanical construct for an exit ramp is your best idea to avoid an ugly fence. And a fence would have to be pretty tall to keep out deer if there was a drought and you were one of the few water sources left in the area.
