UCI compliance for equipment is easy. Buy UCI compliant components and go to a fitter who knows how to set up the bike. What is hard is developing strength and adaptation in the UCI position that may be a bad fit. Ostensibly, UCI put the majority of racers, independent of morphology on the same setup for time trial. And we are allowed one morphological exception. I set the nose of my saddle 5cm back from the centerline of the cranks and then moved the bar extensions to 80 cm versus 75 cm since I am taller with long arms.
That setup means I ride on the nose of the saddle that is not that comfortable and I am limited in the amount I can slide forward and back.
Enforcement of UCI tech rules by USAC is a function of the race promoter and head USAC official. At the LAVRA track time trials, we are not allowed to have any visual indication of metrics while racing. I tape over the head unit but the preferred way is to mount the head unit under the saddle. These are USAC sectioned events but follow this UCI rule but not bike compliance.
What UCI takes off the table are modifications or MacGiver stuff. So clipping on anything or putting on tape or whatever is not compliant.