Difference between db_owner and having all other database roles except the 2 containing the deny keyword What is the difference between having only the db_owner database role and having all other except db_denydatareader and db_denydatawriter?

db_securityadmin +
db_accessadmin +
db_backupoperator +
db_ddladmin  +
db_datareader +
db_datawriter

Versus

db_owner

I've read that when you have db_accessadmin and db_securityadmin roles, you can change database role of another user into the database but I tried and it seems that I don't have the permission to change any permission while logged with this user. But if I give to this user the db_owner role, now I can change permission to any other user.
As per the Docs article, db_owner can perform functions that no other role or combination of roles provides, including but not limited to:


Adding users to fixed-database roles
Dropping the database
The CONTROL DATABASE permission


There is a diagram on the linked article that shows the fixed-role permissions for each role. Any permission not listed in that diagram is granted to the db_owner role only by default.