If the Redshift icon no longer appears in the taskbar, the application remains active, provided that you launch the geoclue2
service at session startup, as indicated in this post of @Staudey dated 07/29/2023:
https://discuss.getsol.us/d/9569-sync-updates-for-week-30-2023/15
That said, there is a good alternative to Redshift, it's the Budgie Night Light
applet.