The traditional comfort bike is generally a heavy low end bit of silliness. A super low travel but very heavy suspension fork, in many cases a vintage quill stem and lower to bottom end components with poorly designed suspension post that is really a pogo stick that will allow for a rotatable saddle which is generally quite massive and super heavily padded. It is not necessarily a comfortable bike but it is designed to seem comfortable to someone who may not know a thing about bikes and is willing to compromise most everything for a look of comfort.
If you want a comfortable gravel hybrid build one yourself. The
Marin Headlands would be a pretty nice but not super expensive frame to build up. Add a AXS GX groupset,
a Kinekt seatpost (available in carbon) and maybe some
Whisky Scully Bars and some
Ergon GC1s and you have a pretty killer but very comfortable gravel flat bar. I built up a similar bike (sans AXS and Kinekt) for a customer and they love it. Granted theirs was set up more for the road but you can fit I think 700x45s or 650bx50s so you can have some good comfort there and a pretty light bike. I think the one we built was about 17-18lbs or so and with some lighter wheels it could have gone down a good bit. For wheels Astral is a good go to for me, I just semi-recently bought a wheel set from them (after buying a single wheel from them) and they are fantastic. They are the same folks from Rolf Prima and I believe are owned by White Industries now (or possibly the other way around) but should you desire to get other hubs they offer a lot of options but I think value for money on US made hubs White Industries is hard to beat.
I wouldn't generally go for an already built bike if I know I want something more custom unless no frames exist but there are so many great frames as well as a ton of great frame builders you can pretty much go for the moon.