Yes, this is poor design. Built and Tested by Monkeys.
https://support.google.com/mail/answer/56256?hl=en-GB will show you how to set up a Gmail account.
https://www.microsoft.com/en-us/microsoft-365-life-hacks/organization/how-to-create-outlook-email-account describes how to create a microsoft (live/outlook) account.
Apple users it's a little less straightforward but not bad. https://support.apple.com/en-gb/guide/icloud/mmdd8d1c5c/icloud
I mention these three because most people would likely use a Android or iPhone, and if they have a computer it would likely be Apple or Microsoft (OS) based so the above slots in good with what you may have.
After you set up a new password on your Virgin Media account you also need to generate a new Virgin Media APP password - Because Virgin Media have copy and pasted your old password into other systems (Monkeys).
If you do find all of this too bad and too much hassle you can phone them and they will set a password for you over the phone - But AFAIK they will not change the APP password, you could try because I would expect someone in VM Land to eventually learn how to do something.
They call it an APP password because it's a external Application - This is really confusing using a term like that when people think of APPs as something you get on your phone.