To be clear you are saying with the smart object you can only do one filter which will be RE-Editable. Any extra filters on the smart object means you cannot Re-Edit.
No, I'm not saying that Louis, and I'm not sure how I have given that impression. As shown in the screenshot, you can have multiple filters (SFX isn't on this Mac, but it would be listed like the others).
When you have multiple smart filters, each needs to be recalculated whenever you double click the smart object to re-edit in ACR, but in general you'll have done all your ACR adjustments at the start and won't need to keep reopening it.
Another restriction I found is after using NIk on a smart object I can no longer use tools such as dodge or burn, or am I working incorrectly.
Yes, the smart object layer is protected from pixel editing tools such as dodge and burn. That's a general characteristic of a smart object.
However, this makes you adopt good practice like putting edits on layers, which you can easily remove or fine tune in later PS sessions. This photo doesn't need any editing at all (!) but here I show a layer for cloning (often I'd clone away each problem area on its own layer). There's also a Curves adjustment layer with a mask as if I am burning around the edges. In a year's time, I may decide I don't want that edge burning, and so I'll simply hide or remove that Curves layer. So I see the restriction as an advantage.
