Construct does have a built-in export to Xbox One. And, as far as I can tell, virtually nobody uses it. Posts like this are always a little mystifying to me: we do actually support this for Xbox One, but it's not mentioned at all by anyone - everyone acts as if there's no console support whatsoever.
My best guess is everyone already uses third-party porting services. And if you're using a porting service for, say, PS4 and Switch support, it's probably actually easier to get them to cover Xbox while they're at it. Hence, nobody is using the built-in option.
I'm greatly concerned that we could do months or even years of extremely costly work and then still nobody would use the console option at all, because people have basically found a workaround in the porting services and will just carry on using them. I think the console makers are also fine with high barriers to entry: they want to make sure only high-quality content that can jump the hurdles gets on to their stores. Also if consoles don't have built-in support for HTML5 games, then given our dependence on browser technology, creating a highly compatible engine port is borderline infeasible, amounting to writing a significant chunk of a browser, which is normally done by huge corporations with thousands of staff. AFAIK, the third-party porting companies are just maintaining compatible subsets of the engine, and do bespoke work per-project to adapt them to work.
The existing Xbox One support is based on JavaScript UWP apps, and as far as I can tell Microsoft are actually trying to slowly phase those out. So with such little usage, an apparent lack of on-going support, and the apparent failure for this option to even enter the conversation, I'm more inclined to remove this option and allow everyone to use third-party porting services instead. I would guess our efforts would be much better spent helping make life easier for the porting services - but so far they seem to be getting along fine without needing much from us.