Hi All.
This issue is not Garmin related.
I have Xiaomi Poco F3 phone with stock Android 13 ROM. I have two SIM cards, one UK Vodafone and second one is 1p Mobile (EE network carrier). WiFi calling is enabled on both SIMs because I have poor cellular reception in my area but perfect WiFi in my house. But only Vodafone that is a real pest with their never-ending notifications. Disabling WiFi Calling is not an option for me.
When I run custom LineAge ROM on the same phone I had no such issue. I also did not encounter the same on Motorola Moto G31 phone with same two SIMs. But more and more I incline to think it is Vodafone that keeps doing this even if they may not admit it.
I run the search and found an article on XDA Developers forum with the solution.
Someone under nick @otonieru suggested “Use nCleaner app from play store, and under "Ongoing notification" section, just disable any notifications you want to hide”.
Notification Cleaner (nCleaner) has worked for me. I got rid of the frustrating Vodafone WiFi calling notification. It now does not come up on my Garmin Forerunner 255S, so I no longer need to clear these annoying notifications that otherwise I was not able to block.
I hope this helps to you and anyone else.