Shalom, I have a vac and it has been a good assest, and it has cleaned the pond better than I expected for getting crud off the pond bottom and flat surfaces aas well as what was floating in the water but this portion was a very slow process and I ended up getting a dirty water pump.
I bought a dirty water submersible pump that would pump solids, I believe it was rated to pass solids up to 1/2" (?), set it at the pond low point and pumped the water into a trash can with a 2" drain pipe bac into the pond. over which I had a slip on filter sock over the pipe - by far much, much faster than trying to clean the water via the vac.
It took the pump, I guess, a total of 8-10 hours, or so, to get the pond clean, but the pond had not been cleaned, except some netting, for many years.
I've since installed a retro bottom drain that appears to be doing very well. I plan to keep the vac handy, nice way to do a quick bottom cleaning if we're going to do some entertaining, same for the dirty water pump.
I like to have handy the tools that I might need or make ponding a bit easier.