How to collect water from small stream more effectively?

I have a tiny trickle stream on the land. It is not much but I would say, having dammed it, that it fills quite quickly, maybe 0.5 litres per minute from empty.

I know they say that dammed water is bad because it causes stagnant water but that doesn't make much sense to me since water butts are dammed 100% and stand for weeks or months don't they and a dam with water still flowing through it, albeit slowly, is still much less still than that isn't it?

The issue I am having is how to collect the water using gravity. I know I could get a manual pump on the dammed bit, which I may try at some point, but I would like to use gravity for now.

I have dammed it near where it comes out on the land and the pool contains maybe 20 litres or so. I also dug a step in the land below so that my 10l water bottle would fit underneath.

My mother had a spare piece of shower pipe with a curve of 45 degrees so I used that on the dammed bit to protrude over the edge with space to allow the container underneath to catch it.

The issue is I am only able to get a trickle coming out consistently. I am wondering how I can make more pressure? Is it because I put the pipe near the surface and would, rather, putting it to the bottom cause more water pressure to force it through more?

I also have a thin mesh like muslin from some food packaging I had. It was a pea net. I used this as I noticed there are quite a few little water creatures in the water and so would not have wanted them to go into the container! Also other inanimate things like little bits of wood or other debris.

This does impede the flow but it is also important to filter the water. I am filtering after this for my drinking water with a gravity filter but this is just to get rid of debris. I have been playing with putting gravel before it as well. That gets rid of bigger bits to stop it getting blocked up as easy. I tried putting some sand in for further filtering but it blocked things up almost completely! I put on the other side instead and seemed better.

I have been able to find a sweet spot now and then when the little pool of water between the gravel and the pipe mouth forms suction and it suddenly gulps the water in that little holding pool and makes a big gush and 'Shloop!' noise, which is rather satisfying, but I haven't figured out how to consistently get it to do this. Or I had it for a few days and then the weather changes the water level or some erosion takes place and it stops working and goes back to a small trickle.

So how can I make a more consistent flow through the pipe? If I put it lower in the water of the dam I will have to dig down more in the step below. I might be able to but not sure if I will hit some hard rock which will impede things.

Open to other ideas. I have looked online and not seen much relevant to my case. Most stuff talks about gypsy wells to gather waters from small streams and I read they are finite anyway, only lasting a few days before having to make a new one. I would like to work with what I have done so far as I am happy with this setup if I can get the flow consistent.

It took about 10 minutes today to get a full container of the 10 litre one.

I use a rubber water heater pan that has a hose bib outlet.
I inserted a short 1" PVC pipe into the hose bib, and that feeds a 2" pipe leading to our reservoir
I had to excavate to get the pan low enough that the water would flow into it.
My water is up on the mountain, so gravity flow is not a problem.
Debris and animals (deer and elk with the occasional bear) cause the most grief.

In your situation, I would screen for large debris and then take your 10L bottle and strain it better at home before drinking.