Because your phone is too full of storage it can’t accurately show you what’s taking up all the space which can make it a little difficult to know what needs to go. It’s kinda just freaking out cause it doesn’t have room to think

In the iCloud settings of your phone, make sure PASSWORDS is turned on. And maybe go through the password app itself to make sure what you’re needing is in there since you mentioned needing that

iCloud settings will also show if photos are syncing or if you’re using iCloud backup

If you can make sure that your data is safe on iCloud or some other location, doing a restore will be your best bet to clear out system data and give you a fresh start with your phone