You shouldn’t without research, and some are worse than others.
See:
- general overview: Comparison of Android ROMs
- Kuket’z coverage: Android: GrapheneOS, CalyxOS und Co. unter der Lupe – Custom-ROMs Teil1 ⋆ Kuketz IT-Security Blog
- my notes Patch Levels - DivestOS Mobile
- Android Recommendations: GrapheneOS and DivestOS - Privacy Guides
- Choosing Your Android-Based Operating System | PrivSec - A practical approach to Privacy and Security