It’s never really strong. The door closes and builds up pressure from the weight of the pool water. The water wins and knocks the door down which gently floods the skimmer and sucks in whatever is close by.
I agree the water looks too low for optimal skimming. Halfway up the skimmer mouth is the best level. I personally liked mine a tad higher in case some evaporated.
Your water level is way low in the skimmer. The skimmer basket should be at least half full with water, if not 2/3 full.
You should not see any water movement when looking into the skimmer. The top water should be almost still.
Toss some ping pong balls into the pool and leave it for a day. If the ping pong balls find their way into the skimmer then it is working properly.
I can see a bunch of leaves and pine needles on the surface of my pool. If I stand there I never see them go into the skimmer. But if I came back the next day the surface is clean and the skimmer basket is full of stuff. Skimmers work like subs, slow and silent.
If you hold the weir door up, I think you'll see that the basket goes dry fairly quickly. I think your water level could be a touch higher - but do you have a concern or are you just curious? I've turned my main drain line basically off, only open the smallest amount, which forces all the suction to the skimmers. Performance has been way better and it's collecting 99% of the debris on the pool surface.