I don't mind being shut down as I hate to do stuff twice or in a way that doesn't work!
Chemical would help with fishing, just not so much for swimming...
Extending the dock might just be the way to go.
Thanks for your input.
I don't have additional ideas, but I can shoot a hole in a couple that you listed if you will allow...
Chemicals to control the algae could do just that, but the silt will still be there and IMO the silt is still "yucky".
Using a backhoe to clean out the silt will only be temporary as the surrounding silt will soon slump into the fresh hole you've had dug so it's temporary at best.
I'd do like the idea of extending the dock out to deeper water.