Haptic Notifications not working on iPhone 15 Pro Max

I see that this has been reported by a number of other owners experiencing the same problem. In brief, the haptic engine is working for everything other than notifications, so cannot be a hardware failure. When the phone is on silent and haptic notifications are all on, the phone doesn't trigger an onscreen notification and neither does it vibrate. Believe me, I have tried all the various fixes posted by the community here and online, and nothing has cured the problem. I've also spent hours on the phone to apple support and they can't fix it despite endless wiping and starting afresh with a new install, both from backup and fresh install as a new phone. Not having either visual or haptic notifications means I will need to return the phone for a refund. Not ideal really so, before I give it back to apple and stick with my old phone for another year, has anyone who has tried the many fixes posted here found a solution? And are there people out there like me, who have tried a multitude of fixes and not been able to find a solution?