A photo would be helpful.

If you have an effective groundcover, and around here there are a bunch of ferns that work well as groundcover, adding some new perennials, shrubs or small trees inset into the ferns to add interest might work better than changing out something that is working to control erosion along the water. Getting new plantings established on a slope can be difficult when one considers weed control and erosion during the time something is getting established, and many plants aren’t happy on a slope or won’t provide effective control for erosion and slippage.

There are also rules that effect what you can do along public waterways because your erosion issues can effect water quality for everyone along the same waterway. So be sure to research how those laws effect what you can do since fines can be steep and you might be required to return everything to its prior condition. Or hire a designer who is well versed in the legal aspects of design along shorelines.

In Fort Myers, FL. I would suspect you have a species of Boston fern, Nephrolepis sp. growing on this steep bank. When a plant is doing its intended job, it isn't always wise to recommend changing things. I do know these ferns can get ratty looking over time with the buildup of old leaves.

Try mowing/cutting the ferns down and removing all the current growth. Fresh new growth will quickly regrow and you might find the new fresh looking ferns are quite tolerable.

Mimosa strigillosa might be a good solution - it is low-growing, has deep-rooted, tough runners and pretty purple-pink flowers that bees seem to love.

https://www.south-florida-plant-guide.com/sunshine-mimosa.html

P.S. When mine dies back a bit in winter, I overseed it with winter rye grass.