Hey Charli
I understand that software upgrades (16 to 17) can be frustrating since compatibility can lag behind with older devices but don’t worry that is something that apple software engineers are always on the lookout to patch with incremental updates (ex. 17.4 pr 17.4.1)
what you can do is make sure that analytics and data are set on and to be shared with apple so the apple software engineers receive bug infos or defective codes asap here is how you can do it:
go to Settings > Privacy, scroll down, and tap Analytics or Analytics & Improvements. Then tap Share iPhone & Watch Analytics
You can also call Apple Support as well
Keeping automatic updates (under settings > general > software update) on is the first advice I have for you in order to receive the latest improvements on the software
Secondly here are a few settings that could help with your iPhone performance starting from:
- Deselecting background app refresh for apps u don’t want to be active in background:
Settings > General > Background App Refresh
- Another issue that might cause performance decrease is also app tracking:
Go to Settings > Privacy & Security > Tracking
Go to Settings > Privacy & Security > Location Services > choose to never for apps that don’t need to recieve your location
- Check your storage as well because that might be causing the issue too:
Settings > General > iPhone storage
- Feel free to check this guide as well for more detailed help:
If your iPhone or iPad is running slow - Apple Support (IN)
Hope this helped resolve or at least ease your issue
For more help or troubleshooting steps you can contact apple support via:
Official Apple Support
Best Regards
Rinas