When I upgraded from the Xbox one to the series x, I transfered all my game data to an external drive and them moved what I was playing the most onto the Series x, and didn't notice any change in game data/progress, so I think what you are asking is possible.

Is there a cloud system where it auto uploads all your data and saves to the cloud and then you can just easily re-download it another console?

I don’t know about Xbox but auto uploads of your data exists on PS4/PS5 and let’s you download them on another console so you don’t have to lose anything ever so I’m sure Xbox must have their own alternative version of it?

You mean the games? As pointed out it's easy to do with an USB hdd, or of you have both consoles in the same network then you can enable remote transfer, so the downloads are made from the other one, instead of the internet. Any removals of the internal disks aren't supported.

Would it be possible to keep the accounts too? I'm sorry I'm specific. 😂

External HDD can have games OR media, I don't think it can have profiles or save data (but I'm unsure as all that stuff seamlessly stores on the cloud anyways nowadays).

When I moved to series X, I justed logged in using my profile, if your refering to profile data, this is not only kept on your systems hard drive, but on Microsofts Azure servers also, so theres no chance of you losing it. As for games can swap em using any external HDD/SSD. If you have a lot of games on a external, might be worth getting a external nvme SSD, (once downloaded games can be swapped back and forth within a couple of minutes), others work fine and don't need the super expensive series s/x dedicated one.

Just sign in on either console you are using at the moment and it will sync as long as you are connected to the net.

Hard drive wise, grab an external USB 3.0 SSD and copy your Xbox one/360/OG games to it and then you can use it on either console.

Mate every game is cloud saved so you won't loss data and if your really picky on some old game just look it up. So when you get a new xbox just sign in and start redownloading your games, if you have an external hard drive you can plug it into your new xbox so you don't have to redownload some of the games although a lot will want to be enhanced.

The games yes, either use an external drive or have both in the same network and use the network transfer option.

The save games are typically in the cloud as well as stored locally, I’m not sure how to check the status of that.

Accounts are not possible to be moved, you’d have to sign in with those from scratch, when you log in the console asks if you want to duplicate your settings from your previous console or start fresh.

I know it's a weird request, but would it be possible to transfer NOTHING via the cloud and keep all data. I would like to keep an old friend's account on it even though he forgot his password and got locked out. I know it's odd, sorry.