Did some research and found many iphone users having the same problem, as it seems due to the nfc chip breaking down:
https://discussions.apple.com/thread/252721492?login=true
Called Apple and they did a diagnose of my phone, but they couldnt detect a defect with the nfc antenna. Now they recommended to go back to default fabric settings. Doubt this will help, but probably will have to do it in order to get a warranty repair or replacement.
Put on a new sensor and started it with the libre reader. Old sensor is also still on my arm and sending alarms to my phone through bluetooth (but cant be read/scanned). I’m Leaving the old sensor on as it is pretty convenient to get repeated alarms until your bg is actually back within range.
(Normally the alarms stop after making a scan, leaving the risk that you remain out of range for quite a long period without being warned by an alarm. As this old sensor cannot be scanned, it continues to give alarms until bg is back in range. Repeated alarms as an option would be a great addition to the libre app)