Is there a noticeable difference between Series S and Series X playing Original Xbox and Xbox 360 Games?

I know that the Series X plays the One X versions of them, which are 4K. Though I believe they should run at 1440p on Series S, does it mean that all One X Enhanced games will run at 1440p on the Series S?

I have a gaming PC and PS5 so any First-Party games I'll play on PC anyway.

I'm also aware the Series S has no disc drive. I would be getting the Digital Series X anyway if I was to get the Series X. Figure I would save myself $150 to get the 1TB Series S over the 1TB Digital Series X.

So as a strictly backwards compatible machine (maybe minus like Rare Replay that's not on PC or the occasional Series S|X Enhanced game) is the Series S fine?