If the ROBLOX app would adopt the ability to use the password stored for ROBLOX.com for a specific username to login to the app, it would make the login experience much easier.
This sounds like it’s your problem. When designing a long password jumble a load of easy to remember things together in a specific sequence, then just remember the sequence. It’ll be easy for you to remember and very difficult for others to guess.
I can see how this would be useful, but maybe the reasoning behind it isn’t quite right.
Maybe the reasoning behind “designing” passwords isn’t quite right either and generating passwords is better than designing them. I’m pretty sure that any password that can be remembered by a human is either going to be reused in many places or is not secure against offline attacks. I doubt people can remember more than a few random passphrases, too, though that would be a better option than passwords now that there is no longer a 20-character limit…
Password managers are not only more convenient but also more secure; they just need to be supported by applications.
Easy enough to remember… Mom’s birthday, first half of middle name, favorite animal (with an exclamation because it’s your favorite) backwards in capitals, Dad’s birthday backwards, second half of middle name.