I had same issues with my s22 ultra. For the first roughly 10months. All started off alright then a month or 2 after getting it, it all of a sudden started not having any mobile network at all and was only able to recieve or make calls or send texts etc whilst I was connected to WiFi. Did alot of research and in the end i took it to a samsung service centre and they said there was a fault within the phone itself (no physical damage what so ever to the phone) they fixed the problem along with the battery and couple other things free of charge.
Phone worked perfectly reception wise after that. Did however have a snowball effect with different issues after repairs due to new battery the put in overheating and cracking the screen and causing issues with the motherboard aswell as faulty keyboard port etc. So not likely I'll purchase another s22 ultra on the future. Previously had an s21 ultra and that was one of the best phones I've owned, not too sure what went wrong with the s22 model 🫤 unless I just got a lemon 😔.
On the main Community page, top right, is a search button. Open it and enter "Wi-Fi Calling Continually" 12 December. Some of my responses there may overlap with your problem. Especially Access Point Names. The number of bars showing is not relevant to wi-fidisconnecting"
It is not a solution but have you checked if wi-fi calling is on? Google "Telstra wi-fi calling". This may not work if APN settings are wrong but otherwise a major help in receiving and making calls when logged into any nearby wi-fi network.
