STM32 Repetition Counter
The repetition counter register documentation tells us that it only uses the lower 8 bits, so the maximum value is 255.

To do what you want to do (generate an interrupt every 1 second), you should use a capture-compare register which are 16 bits.

I haven't used the repetition counter yet, but from what I can gather in a short reading, it's probably there for some motor control stuff where you want to change the PWM frequency after a certain number of periods of the current PWM frequency.

Also try to improve on your units handling. Periods are commonly measured in seconds and a frequency divided by another frequency gives a result without a unit. (Units can be very helpful to check if you have calculated the right things)