Current message is:

history syncer #1 [processed 0 values, 0 triggers in 0.000447 sec, idle 1 sec] 

However there are several transactions in history syncs so it should write that statistic for each transaction for example:

1056121:20250120:111229.163 zbx_setproctitle() title:'history syncer #1 [processed 200 values, 0 triggers in 2.941335 sec (history: 1.6 sec, update: 1.386309 sec, trends: 0.0 sec, triggers: 0.0 sec), idle 1 sec]'

Including more statistics as in example above could help determine which transactions are slowest, in the example above lots of time is spent updating lastlogsize, in other cases it might help to know if something is slow with the triggers.