Hello.
Thank you for sharing your experience so openly – that really helps to understand what’s going on. It sounds like your iPhone needed some time after the system backup to fully complete background processes, which can happen especially with older models or large data volumes. The fact that it returned to normal after 24 hours suggests that the system was still stabilizing, possibly with things like Spotlight indexing or iCloud syncing running in the background. If your iPhone is now performing well again, that’s a good sign. If the issue comes back, performing a fresh backup and restoring the device could help. I truly appreciate your patience – it’s not always easy to wait it out, but your approach was spot on.
Just a gentle reminder: We have a dedicated community for English discussions over at discussions.apple.com. Since your post is in English, we warmly invite you to join us there for further discussions. Thanks for your understanding!