By the way, I would strongly discourage your score structure:
\version "2.23.81"
timing = {
[\repeat segno stuff]
}
music = \fixed c' {
[without \repeat segno]
}
\score { \new Staff << \timing \music >> }
LilyPond does not make efforts to support differing repeat
structures across voices / staves / parallel music expressions.
Sometimes it works, sometimes it does not. Potentially, it
could break in a future version. (This has partly happened
with volta repeats in 2.23.)
It is much preferable to use \repeat segno in all parallel
expressions, i.e., get rid of your timing variable (unless
you have other stuff in it) and use \repeat segno in the
music itself. (In all voices / staves / ...)