Just wanna throw in a voice saying your setup sounds completely fine to me. Maybe it’s a bit odd but it also sounds like how I’d do it if I had storage needs that large.
My current storage needs are currently met with a 2.5" SSD connected to a raspberry pi shared with samba over WiFi though so I’m pretty sure every storage nerd in here is gonna tell me my opinion doesn’t count, take it with a grain of salt.
So, most windows installations come with an OEM key because it came pre-installed. OEM keys, last I knew, don’t have this support, because the manufacturer is responsible for that.
If you bought a lenovo laptop, its on lenovo.
But anyone has been able to buy windows directly with a standard license key and windows supports those computers directly. I’ve never bothered to use it but I worked with people who did and (again, last I knew, some 10+ years ago) they got someone with a thick accent reading from some support article who didn’t know what they were about.
But they could call. Technically that’s support.