What you can do for your ringer volume is decouple from media volume (Settings > Sounds & Haptics > Change With Buttons > off). This prevents them from being changed when you press the volume buttons and keeps them at the volume you set in Settings.

Also regarding alarms, did you set a standard alarm or a wake-up alarm? A wake up alarm is set when you set up a Sleep Schedule and has its own volume controls that are not affected by the one in Settings > Sounds & Haptics. Also if you’re wearing your Watch to bed, it will try to wake you up using your Watch using taps first and then sounds (make sure Silent mode isn’t on in the Watch’s control center)

I think it needs to be connected using a Lightning to USB-C cable. Wireless wouldn’t work

Another thing you could try is downloading iMazing and see if it shows up there

If you connect your iPhone to your Mac, does it show up in Finder? If it does, try to click it. Make sure ‘Encrypt local backup’ is on, then click the “Back Up Now” button (It should trigger a manual backup to your Mac even if your iPhone is set to back up to iCloud). Source: https://support.apple.com/en-gb/guide/mac-help/mchla3c8ed03/mac

If you get a new phone, it will have to be on iOS 16.0 final release or newer version before you can restore a 16.0 beta 1 backup to your new phone.