All tempo is relative.
Unless you are playing with a metronome, it is really difficult to maintain exactly the same tempo throughout an entire movement.
Why would you want to, anyway?
The more complicated a piece is harmonically, the more time a person who is listening needs to process the music.
The same goes for serious leaps in register.
Many composers write metronome markings that are too fast.
Sometimes composers write metronome markings that are too slow.
The same composer can do both.
The right tempo is the tempo that is right for the people playing and the acoustics of a space.
The right tempo is a tempo that is within the technical capabilities of the people playing.
The right tempo for you and your musical partner(s) may not be the right tempo for me and mine.
The tempo that happens in a rehearsal may not necessarily be the tempo that will happen in a performance.
But that's just fine.