Bench Questions (Bar Speed)

So a friend of mine who is a lot better powerlifter than I am noticed me doing a dynamic day for bench and told me to only do that if I had poor bar speed to begin with in the bench press. So my question is, what is considered “poor bar speed”, how do you evaluate if your explosiveness/speed is a weakness in your bench? After examining my bench I feel as though I do have poor bar speed, as reps are often slow and grindy but I don’t know if thats just in my head or if it’s actually slow. Your input would be appreciated guys.

A side question- how much carryover does standing press have to bench press? I ask this because I have never put a focus on the press in my training but I can still do bodyweight which I consider a good starting place. If I started to emphasize heavy pressing in training can I expect to see it help a bench plateau? Or is that foolishness?

thanks