Good quality, shielded cabling and an interference-free network are important for passing high-bandwidth audio streams without issue.
I have used a Sky Stream puck, an Apple TV 4K (gen3) box and a Homatics Android TV box regularly over the past few years and have only had perhaps one or two Atmos drop-outs in that time. Both came from the Stream puck and were likely caused by small speed fluctuations in my home broadband network or a server-side issue at Sky's end.
The Atmos decoding device is also a critical part of the chain. Be it a soundbar, a TV, or an AV receiver, they can all suffer from random electrical interference or processing slow-downs which can cause drop-outs.
A cheap soundbar may have Dolby Atmos decoding capability but there's no guarantee it can decode a Dolby Atmos stream effectively at the speed necessary to keep it in sync with the picture. Most need to regularly flush their cache in order to keep up with the incoming audio stream, decode it and output it to the speakers. If they don't have sufficient processing power to maintain such a process then occasional drop-outs can occur. In such a case, it is not the source device which is at fault, it is the soundbar.
I'm not saying Sky aren't at fault here, they clearly have acknowledged issues with Dolby Atmos, but for an effective Dolby Atmos presentation in your own home you need to look at every component you use in your A/V setup.
