All the baby joggers have a carrycot option, compact, compact plus and the now hard to find deluxe. They do lie almost completely flat anyway and have always been sold as suitable from birth. There have been some new regs relatively recently that seems to have impacted on what is sold as that, seemingly now there has to be some sort of enclosure so lie flat alone isn't meeting that anymore. This is new stuff though, existing pushchairs sold as suitable from birth still are.
My personal baby jogger issue is that they have wide wheelbases, i believe the cmgt is only 1 or 1.5cm narrower than the vista. The fold is totally different though. Totally.
Sooooo many people are looking for a more robust pushchair the approx size of a bee.. you're not missing anything, there isn't really anything. The easywalker june sort of but it has issues with parent facing handling, seat position etc.
The new easywalker mini stroller is apparently a contender in this category but as it isn't out yet we don't really know.
They don't come much lighter than the cherry, cruz or bee with the features you are looking for.
I suppose you could look at something like the cybex callisto, that has a lovely carrycot then turns into umbrella stroller with bar handle. I had one and loved it as a pram but didn't like how it handled as a stroller. It's much sturdier feeling than a bee (imo, this stuff is certainly subjective) but by no means a terrain option.
The new britax b motion could work for you, that takes the full size britax carrycot, is 58cm wide and folds as the baby jogger does. Or possibly even a mountain buggy swift with carrycot.
Imho there are a lot more sturdy options that go carrycot then forward facing seat. If you want parent facing beyond the carrycot stage almost everything that feels robust is bigger and heavier unfortunately 