iPhone storage quickly refills after deleting data

I have deleted data from multiple apps on my iphone, and yet the storage keeps filling again very quickly, even though I have not downloaded new apps or data through my apps. This is really really frustrating. These are the things I have tried already:

• My icloud backup and sync is off. My photos are also not syncing or uploading to icloud (I chose to backup somewhere else).
• icloud storage: about 400 MB is used out of 5 GB. When my phone storage keeps filling again, this is not affected, which means data is not uploading to icloud (which is fine, as I don't want to backup to icloud)
• I always delete photos and videos from the "Deleted folder" to ensure they are gone from my device.

I am using iphone 13 pro, with software version 18.4.1 - although I have had this issue with multiple software versions, so not sure if this is a software version issue or a settings issue, or something else.

Even after deleting 3 to 5 GB of data, the phone storage becomes full in the next two days, without any changes from my end.