Xbox developer mode [1] appears to require a valid, current Partner Center app developer account [2]. Individual accounts are $19 and "With a developer account, you can submit apps and games to Microsoft marketplaces, including the Microsoft Store."
so you dont need a devkit but would need an Xbox and you do need an account to publish. so yes, while you dont need a xbox dev account to program, you dont need an apple dev account to program either. you just need a dev account on either platform to publish.
[1] https://docs.microsoft.com/en-us/windows/uwp/xbox-apps/devki... [2] https://developer.microsoft.com/en-us/store/register/
In Microsoft's case, UWP on XBox doesn't count as it is castrated to the actual OS capabilities, and hasn't been updated for a while and most likely it won't.
In some version of Visual Studio the SDK can be downloaded from within the program.
XDK: https://docs.microsoft.com/en-us/gaming/xbox-live/get-starte...
The XDK (aka HDK) includes physical hardware and is intended for more demanding games.
Sony SDK: https://www.companyregistration.playstation.com/SCEInternetA...
The Sony SDK and HDKs are available to registered partners only, though registration is free and the SDK (but not the HDK) is free to all partners.
Sony and MS games can be programmed without licenses or devkits (which make it much easier to debug games by providing debug access not available on retail consoles).
Moreover, devkits are frequently made available for free by both companies to indie developers and even major partners.