Email dosen't match upn user in hybrid exchnage env

Hello ,

for a specific request , we are created users with Email is different for their upn

user1 upn : user1@xxx.com and his email is user1-bis@xxx.com and Primary proxy smtp is : SMTP:user1@xxx.com

we are in hybrid exchange env and we are using azure ad connect to sycnhronize users to azure

the proble in this case , when user1 is synchronized in Microsoft 365 portal .i have seen in his aliases user1-bis@xxx.com which should not be there and when i see his outlook profile .it's showing that have two emails ( user1@xxx.com ans user1-bis@xxx.com) .how we can resolve this issue because we need to show just user1@xxx.com in his outlook profile

Thanks