Hello,
So from the ground up, all systems are different.
To the user area or customer center:
We just look at "Blesta" here you can see very clearly that they have copied the user page from WHMCS the reason for building for the user is almost 1 to 1
Unfortunately, I can't say anything about the other systems at the moment because I haven't looked at all of the systems carefully
With best regards
Detlef
Wisecp - Discord and Forum Moderator