What do I need to replace?

[MaggieMae]

Hey folks, it's the part on the right, the gray doohickey that I hold down to get more water in the bowl. Because the bowl doesn't fill back up all the way
when I flush with either button. What should I replace or is there an adjustment I'm not seeing?Thanks!

 

[breplum]

there is flow control (blue knob with pointer) and float adjustment (round knob) on the fill valve.
It is Fluidmaster 400H Performax series....endless videos i presume on youtube

 

[Rickyman]

It's tough to tell from the angle of the picture but the fill valve height looks low.

 

[GReynolds929]

The black hose should be spraying water into the hole of the blue cap when the tank refills. Does that happen?