IC decoupling capacitor design recommendations
Considering the small green traces leaving pins 15 to 21 at the south side, you probably have completely cut the ground plane connection to pin 22 and pin 14.
It looks like the ground connection from the capacitor to pin 28 runs (way) south of pins 15 to 28, heading north, west of the IC. (Or it runs way east of IC). Anyway, with such a long trace, I doubt the capacitor functions as a decoupling capacitor.

I would recommend to delete all the Vcc polygons/plane, try to swap the mentioned bottom traces (originating from pins 15-21) to the top and apply a decent (uninterupted) ground plane in the bottom layer.
Only when necessary (when traces have to cross other traces), use a vias to swap the trace to the bottom side, but keep those bottom traces as short as possible.