Migrate iCloud data to my Apple email address - can I, and is it worth the hassle?

My primary email address has been a Gmail address for 10+ years; so naturally when I set up my iCloud account and Apple ID many years ago that was the email address used. At present, this iCloud account contains 10k photos, 31GB of Backup data, 24GB of Files and 20GB of Messages as well as an Apple One subscription.

I also have an iCloud email address, which is just used as an alternate email.

I'm a bit for admin hygiene, and have often thought about migrating my iCloud data. I guess there are two plausible ways to go about it - either maintaining the same physical iCloud account space and swapping the email address connected to it; or fully migrating the data to a new account and deleting the existing.

I don't seem to be able to find a simple way to do the former; especially seeing as my iCloud email has a (free) iCloud space of it's own so can't take control of the existing. I'd rather not create another new email address, as both my Gmail and iCloud have the same prefix.

Having my iCloud email manage my paid services and Apple ID feels neater to me than what I currently have. My question is - is this worth it? Has anyone done a similar job and found any benefits (either literal or just scratching the admin itch 😅)?

[Edited by Moderator]