Hi!
You are right; the Stokke Beat is a beautiful, lightweight, compact stroller. It is predominantly an urban model, the city is Beat's second home and won't be fazed even by more demanding urban surfaces, such as lawns or some uneven terrain. Despite the fact that the stroller doesn't have a super soft suspension, the little bit bigger wheels will do the job.
As far as the terrain is concerned... Well, the Beat is not an all-terrain stroller. The truth is that almost any stroller can handle an occasional light terrain. So, it's up to you. If you are prioritizing the comfort on off-road walks, you are looking at heavier, bulkier strollers, which is a toll for the durability they offer. The other option is to go for a lighter, more compact stroller; however, going off-road, the ride might not be completely smooth. Personally, I would go for the Beat if the all-terrain ability is not hyper-crucial (and you won't walk off-road on an everyday basis).
The Cybex Balios S is also urban, so it is not worth considering it as an all-terrain option in the way that it would be better than the Beat.
Thanks to the softer suspension, I would consider the ABC Design Salsa 4. However, the Salsa 4 is a less compact and a more robust stroller.
And how about the BM 4 Plus? Yes, the structure of the BM 4 Plus makes the stroller suitable for such use. However, compared to the Beat, it a completely different, non-reversible, robust stroller, so I don't know, somehow it doesn't fit "into the theme" - it feels too bulky and less practical to me.
And yes, I think in terms of the functionality and the suspension, the Jané Kendo fits the bill. The still compact Kendo can handle even more demanding terrain. If managing some off-road trails is still essential, this stroller is probably the biggest competition for Stokke from all you have mentioned.