No. The halving can most certainly not have a direct impact on transaction speed. You don't seem to understand the difference between transaction speed (usually near-instant) and confirmation speed (10 minutes on average). The reason for which some people are experiencing unusual confirmation times is because they don't include adequate amount of fees.
From what I know it also can't impact confirmation time no?
It doesn't change anything to have fewer miners, difficulty is here to balance things back. Number of tx are defined by the size block, which won't move.