I updated my iPhone XR to iOS 16 too. For the same reasons.
Did my work phone to iOS 15.7 for the security updates but really there's nothing I see that necessitates the update to iOS 16... multiple lock screens? Whoot! The only thing that may be useful is via points in Maps when navigating (I find it works for me before any comments on Apple Maps).
The Synology apps all look to be working (those that work with DSM 7). The more notable update in iOS world is to pCalc and it now having multiple calculators that can be quickly switched.
I posted this to the iPhone Forum, but I will repeat here as it may be of interest. I have noticed one bug on iOS 16 on my iPhone 8. After a reset the log in screen asks for my passcode but does not display the keyboard. Pressing the power button and then home button brings up the same screen but now with the keyboard. (The passcode is required at this stage to enable subsequent fingerprint access.) I sent in a bug report to Apple.
When I updated my iPhone, I don't think that I had the option of 16 and so I installed 15.7. The following morning I updated my wife's iPhone 8 I was given the option of 15.7 and/or 16. Apparently, so I have read, there maybe no need to install 15.7 first.
Btw, I had a problem with the latest update of DS Manager Pro on iOS 15.6.1, whereby it repeatedly crashed when I looked at my memory usage of the DS218+. I sent in a bug report, and had a speedy helpful reply, by which time iOS 16 had been released and I had installed it. With 16 it arrears that the bug has disappeared, so presumably a conflict with 15.6.1. (I did not try it under 15.7)
iOS 15.7 is a security roundup for those wishing to stay on iOS 15... and iPad users, for which there's no iPadOS 16 yet. There's no need to jump from 15.6.1 through 15.7 to 16, just go direct to 16 if it is offered and, of course, if you want to.
My personal experience is that most of the changes in iOS 16 are probably not aimed at me, things I hadn't thought were 'missing', or I have an app that still does it better. Haptic feedback on the keyboard is a nice add-on, though my son says has been on his Android phone for ages. The weather app is a bit better too. Did anyone feel the world move? It's free, slightly improved, but there's no rush
And for those wondering what's new/updated, here's the Apple marketing ...