How can i delete some people on the group chat that haven’t set the group name yet

So, you've created or belong to a group chat, is that correct? Are any of the members of the chat group Android users? If the answer is yes, you can't add or remove anyone once the group has been set up. That is not an Apple issue. That is a cellular provider issue because the messages are not going through iMessage. The only way to remove people from a chat group would be if every single member of the group was an iPhone user, because then the communication goes through Apple iMessage.

Again if just one member of the group is Android, they cannot leave the group, nor can you remove them from the group. And again, that has nothing to do with Apple. That is a cellular provider issue.

Read and follow the article linked above.