Intermittent text notifications after iOS 18 update on iPhone

Since updating to ios 18, getting text notifications is very intermittent. Was not getting any at all, until I reset my network settings. Now they come through very intermittently. There is one contact who has an android phone and I never get a notification of her texts. My daughter has an iphone and notifications from her can work for days and then all of a sudden stop, then start again. My other daughter also has an iphone, I get no notifications from her at all.

Also no notifications for group texts.

I have been onto Apple several times, they have no idea. Have always been a diehard Apple fan, but this issue is pushing me over the edge.

I do not have do not disturb turned on.

I have checked all my notification settings (as has Apple) and they are all correct.

This issue only arose after the intial install of ios 18.

Hoping someone out there may have encountered this and knows of a fix?

[Re-Titled by Moderator]

Original Title: Intermittent text notifications