Forget tubeless mess. Seen way too many guys with tubeless tire being cut and not being able to seal. What a mess on the road. That milky crap will spray all over your bike.
If you want comfort, then just go wider tire. Period. Just keep in mind that the wider the tire, the more floppy it will feel in cornering (tubeless or not!). Think truck tires, good and comfy over rocks, but "jackknife" thru fast corners.
My mtb rims are 21mm internal width, and I run 2.25" (57mm) tires on them.
Most modern road rims are 19-21mm internal width, so you can easily run 28-40mm tires on them (assuming your frame can fit them), but I wouldn't run anything over 28mm if you plan to use the bike exclusively on tarmac. Wider tires tend to be more floppy in corners.
I'm still running inner tubes in my mtb, scooter, and my dirtbike.