Not receiving Messages/Reminders notification on my iPhone

This appears to be a big problem considering the number of similar individual posts I see on the subject. It is a big deal for me. I am ALWAYS missing (not getting) alerts in various conditions/situations/settings.  but mostly when my iPhone16Pro is locked. It started when I got a 15Pro right after I had upgraded from my Xs (which I loved). I then (usually wait about 5 years btwn upgrades) switched to the 16Pro as a trade-in hoping it would solve some of my problems with the 15, but most remained (the primary one the resolved was I wasn’t always having to reset at the carrier level to keep the 5G signal). Anyway, I am most desperate to get notifications/alerts fixed. The two biggest apps for which I am most affected are Messages and Alarmed. It is most evident when the iPhone is in locked screen mode, but that is not always the case. I’ve done all the things laid out in the various answers to date (not muted, not in focus mode, turned on, turned up, Lock Screen on, etc.), but nothing has resolved my problem. 

Open for addn suggestions, and would also really like is a clarification of a section of: Change notification settings on iPhone - Apple Support (IN)

Choose notification sounds for individual apps

You can choose the sound that plays when a notification arrives for an app.

1. Go to Settings - > Notifications.
2. Tap an app below Notification Style, then turn on Allow Notifications.
3. Tap Sounds, select a sound, then tap < at the top of the screen.

You can choose immediate or scheduled delivery for the app’s notifications and where you want them to appear (on the Lock Screen, in Notification Center, or as Banner at the top of the screen), and more.

I suspect the answer is - it depends on the application, but none of the items in step 3 (except the info in the parentheses) appears for the vast majority of the apps I have (so no option to do so for Alarmed). BUT, they do appear for Messages and I have (under Always Deliver Immediately) both Critical Alerts and Time Sensitive Notifications turned on - yet I miss most text notifications (not conducive to a blissful marriage, BTW).  As far as Alarmed goes, I have used it for years, but only began having problems with recent iOS’s.  I really need the audible alert but even the haptic is suppressed. 

As an experiment - to see if it was app specific - I set alarms for my evening meds on four different reminder apps, each separated by 5”: Reminders, Due, Alarmed, & Alarmy.  None came through while my phone was locked. When I unlocked it - I received a barrage of notifications (which is often the case).  I am included a SS of the settings for Alarmed, but all three alarm programs were set the same; for Reminders, I had Time Sensitive Notifications on.

I really hope Apple investigates this as, being an Apple customer since 1984, I have yet (to my recollection) to have anything this frustrating occur with OS or device changes. In the meantime, I was forced to regress to getting a battery operated alarm re-branded as a pill timer and setting it for my med reminders. I took my evening meds on time last night as a result of it going off, BUT would like to get back to using my phone since I am not always where the alarm is, but my phone is always with me. 

Thanks in advance for any attempts to assist. Also, please up-vote this (or what-ever it is called in this group) if you have similar issues so maybe it will be investigated a bit more than it has. I would love it if it were something silly I have ignorantly missed and will gladly cop to it if anyone stumbles upon it; I just want it corrected. 

P.S. - I have a sneaking suspicion that it may be related to communication between iPhones, iPads and MBPs all in the same house, but haven’t been able to pin that down either. Most of the time I am away from home at med time, I have my phone in focus mode, so haven’t experimented enough with that yet. 

[Re-Titled by Moderator]