When you shift you look(if you have to look) at the destination not the transition. Look where you want to end up not where you are traveling.
Practice the transition til you don’t have to look and muscle memory takes over. When you learn the sheets you learn the notes and finger positions no time needed. Once you get that down then put on your metronome or start counting. Don’t learn the sheets and your time at the same time. Timing starts when you practice after you learn your notes.
Like racing you don’t learn your course while going at race speed, you memorized and work out all the kinks before gassing it up and push the limit.