Don't invent anything. Research what others have done and it works. Folks have been fighting this for years and many failures have occurred.

The location appears to be subject to wave action erosion.

The option you describe is similar to hydro seeding followed by a coconut(or other) erosion control mat. This is common on oversteepened slopes near roads or rivers or areas prone to erosion gullies. This could work but you may want to reinforce the bottom by stacking up all the cobbles and gravel near the bottom of the slope.

Another option geosynthetic cellular confinement similar to "geoweb" product. This can be made into steps or laid down along the slope surface.

The overkill solution to resist wave action erosion would be the shoreline erosion manuals and end up with 2 ft diameter rip rap or larger similar to what you see around some lighthouses.

The oceanwater isn’t the primary reason, I think it’s more from exposure to extreme wind (150+kmh) and rain and perhaps frost breaking every spring. The property is in the wreckhouse area of Newfoundland. I walked the beach front and other areas of embankments have naturally fallen off and grass/weeds have taken root and stopped the erosion. That’s where I’m on the fence, to mimic what nature has done or create something.
Here’s a photo.

• https://files.engineering.com/getfile.aspx?folder=8b6908c5-d3da-45d7-a836-e

All that exposed cobbles and a gentle "beach" is a signal of past high wave action. I'd hear from any "locals" familiar with the shore conditions over time and my bet is there can be major wave action. That meager vegetation can regrow rapidly.

Depending where you're located, federal, state/province, or local governments can have restrictions on what you can and cannot put in for erosion protection. I would recommend getting a waterfront engineer involved or, if your local regulators are friendly, you could ask them about any limitations and if they have any recommendations. You could also take a hike up and down the coastline and see what other's have installed and if its still good condition.