I'm slightly above average and in good shape. My take on this is dick size really only matters when, you are trying to get free pussy and/ or young pussy.
In general, providers and majority of women are looking at how big are your pockets.
Honestly, if you're insecure about your size, hit the gym. And manscape.
Being in shape, not only makes you more attractive, but losing that bottom portion of your belly (imo, is difficult, but manageable) could possibly add 1-2 inches to your dick.
Also, better blood flow, can help you do multiple rounds...
Now, with the shape, can't really change that, just do positions where your dick his her g spot.
The best providers give top notch iop, so with great iop, your insecurity with dick size is all in your head.