I think the OEM thing could be their handheld and I think the next box is an expensive Zen 5 console
This is exactly what I think - go after the newly formed handheld pc market - MS version of steamdeck but with platform lockin so MS get all the revenue from the game sales. Also the only time they've been somewhat competitive with Sony in the home console arena is when they launched early. Nextbox is going to be earlier than PS6 by 18months-2 years.
It will be essentially off-the-shelf bits (again) and any "customisations" will be only there to serve DirectX x.y.z APIs (as they've always done in the past).
It will be a jump above the PS5 pro, but coming in early will mean the PS6 will be a gen ahead - in some ways it'll be really nice for hw speculation threads as we'll have them back to back, like going from watching the Euros to watching the World Cup only 2 years later!
The other option is that they choose to do a streaming stick style of thing and push hw into the data centre - I think we're 1 gen too early for that to really work, but they've been working on some of the underlying tech for this for a while so I can see that ramping up - maybe they think it'll be ready in 25-26 <shrug>