I strongly support the suggestion that you look into a veggie filter.
If it has a good bottom drain, you can clean your pond by draining the
veggie filter alone. Just cut it off from the flow. Phyllis and i do
that with our berm ponds on an annual basis. Easy!

In a decade and a half, we have never cleaned the main pond. The muck
is stirred by fish swimming and settles in the veggie filter. The
only thing we pull from the main pond is the sticks and long pone
needles that settle in the bottom of the 'deep well' (old septic tank)
which is the lowest point of the pond.

If you can put one in, a veggie filter is the easiest of filters to
care for.

Good luck, whatever you do.

Jim