Welcome to the community 
The “usual” reason for this is that you are still on Android 9. Murena stopped supporting Android 9 (P) and is still working to make an OTA (i.e. through Settings > System Update) upgrade to Android 10 (Q) and/or Android 11 (R) available:
The only way to speed up things for you would be a new install (Q or R) from scratch.