Only IPv6 on phone hotspot (iOS 15)

Is my phone really delegating IPv6 addresses when it's in hotspot mode? I have devices which are supporting only IPv4, and they are not receiving IP address if I start hotspot on my iPhone 12 Mini. I made some tests with other phones on 14.7 and it really seems this is the new standard, those are working fine. Any idea how to resolve this issue? I do not see the point, it is not realistic that connected devices behind my phone will run out of available addresses. There is a reason why IPv4 is still supported by other vendors.