Why does Hotspot get disabled on Galaxy S23+ when I receive a call?

I recently upgraded (?) from a Galaxy S8 to an S23+. On the S8, I could use the hotspot and receive a call at the same time, without any interruption. However, if I receive a call on the S23+, it instantly kills the hotspot so I can no longer use my computer when on the call. Very frustrating. I tried asking the EE shop to resolve the problem, plus technical support twice. No one had heard of this problem, they say! I Googled the problem and learnt about VoLTE, which I understand prevented this problem on the S8 so that 3G calls used the 4G connection and did not kill my hotspot. Clearly, this does not do the same thing on the S23+. I have tried doing 'network resets' and that doesn't work. I have tried only allowing 4G (in Settings/Mobile Networks) in the hope that VoLTE will work that way. It doesn't! Surely someone else out there has encountered this problem, and hopefully, has a solution? Please help! Thanks