It is difficult to tell how well you are doing while trying to beat a KOM or circuit PR. The game display only shows your ETA towards the end of the segment - you are riding blind at the beginning (i.e, the first 90% of the segment).
When riding outside in RL I use Strava Live Segments on my Garmin Edge to be able to manage my efforts when trying to beat a PR or KOM. At any given time I know my ETA and I also know how far ahead or behind I am when compared to the time I am trying to beat (i.e, my own PR, the segment KOM, or a friend’s PR). It would be nice if we had similar feedback in-game so that we could better manage our efforts to make incremental improvements over previous efforts.