PS5 problems

My husband and I both have our own ps5. We have played online together different games for some over a year ago. We just bought BO6. I bought it and he bought it. We each have our own Activision accounts and we each have our own playstaion plus accounts. It will only let one of us play online at a time. It will kick one of us and throw the code lot connection to host. PlayStation said contact Activision. Activision is saying to contact internet provider. We have done all of the troubleshooting that they have suggested but port forwarding because I don't know how to do that. Anyone else have this problem?