Nice job building the bog. It looks really nice and when the plants mature, it will just look like a planter to the average person. Well done...
As someone already stated, for best filtration your bog's surface area should be about 30% of your pond's surface area. I don't know if your current bog meets that number.
You could always add another stock tank bog. It doesn't have to be all in one.
I feel your pain on building the bog. I did mine in the Spring of 2020. 3 cubic yards of gravel, 3 loads with my pickup truck, transported and rinsed with my wheelbarrow from the driveway to the backyard. I'm no spring chicken either. I had to buy a heating pad for my back!
I can say it was well worth it. My pond water has never been this clear and almost no maintenance is required.