Which phone and message app are you using? I also don’t see a way to view photos or files and which camera app?
Obviously GrapheneOS is the best way to go for privacy but if you do stick to OEM Android then make sure you’re using apps like the Fossify suite. I use their apps with all contacts and calendar synced via davx and self hosted on Nextcloud.
What about KeePass, where is that data backed up?





I self host so the data in the cloud is stored on my own equipment, yes it is still technically online but it saves a copy locally so you only need an active connection to sync new items.
I regularly use multiple devices and having that sync is vital. Even at work, I cannot install software but I can install browser extensions. This means I can use my instance for both personal and work. I have also set up most of my family with access, all for free!