Does anyone on this community have a Oneplus Nord 4 that works with an iD mobile sim only.

A very good day to you all. I’ll try and keep this brief. I currently have a Oneplus 5T phone. I am new to ID mobile. I was with BT where I had no problem with my phone using their network. I have signed up to a 12 month sim only contract with iD mobile, at a very good price. I have ported my old number across and my account with BT is now closed. After activating my new sim, I find that I cannot make or receive any calls. I can however, send and receive messages. I have tried using the sim in a friend’s Google Pixel 7a where it does make and receive calls. So the sim works, but it would appear that the network does not. I have researched this site and others and discovered that many iD mobile customers have had or are experiencing similar difficulties. At this point, let me say, that there was no warning before I signed up, that my phone might not be compatible and why would I think it wouldn’t be, when it had worked perfectly on another network. On my phone, In settings, under sim and network/preferred, network type, it states, 2G/3G/4G (automatic). Under enhanced communications, the VoLTE switch is on and the WiFi Calling switch is on. Various similar threads on this community site advised that I should visit a Curry’s store for advice. So I did. After a 25 minute wait, I spoke to a well intentioned, but world weary adviser, who appeared to not know very much at all. They did however, try a very hard sell, to get me to buy a new phone. They told me, that any new 5G phone would work with the iD mobile sim. Now, I am aware of the list provided by iD mobile of approved phones, that they have tested, many of which they sell, which will work on their network.
So, my questions are: Was the Curry’s adviser correct, will “any” new 5G phone work on the iD mobile network? Also, does any member of this community own or know, if a Oneplus Nord 4 phone, would work on this network. It would be pointless and infuriating, if I acquired one and it didn’t. For context, I came to iD mobile to save money, as I am a state pensioner. My son has a Oneplus Nord 4 that he would be willing to give me when he upgrades, but that would not be for several weeks and I cannot try the iD mobile sim in it, as he lives a considerable distance from me. Gosh, this hasn’t been brief at all has it! Thank you for reading this and I really hope that some kind soul can help. Thank you.