you certainly have the tools to compete at the 4.5 level.... strokes are all fundamentally sound.
the biggest thing I see is you are stiff with your ground strokes... you seem to use the arm muscle make the racket drop, and the forward swing see your arm being a little stiff also.
watch the pros, e.g. Fed, how they use gravity to let the racket drop happen with a noodle like relaxed arm, which they can then whip thru with the core rotation.
the loose arm is not only for better power (free racket acceleration from mother nature - gravity), but also consistency, because it's always easier to give a little nudge to something that is already moving by itself (gravity driven racket/arm drop), then to use the muscle to move something that is stiff and static.
I hope that makes sense... but if you can pay attention to this during your practice, you will understand what relaxation feels like.
interestingly, this stiffness actually makes your volley better than your groundies..... but with improvement you should feel the difference between a loose arm for groundies, vs. stiff (or less loose) arm for volleys