badger_biker 

I'm heading for retirement and considering treating myself to a light and comfortable all purpose bike. That led me to gravel bikes of which I know little.
I'm a C&V guy with an assortment of mid 80's pretty top end touring bikes that I ride for recreation and an occasional tour. My knowledge of the new bike tech hasn't advanced much beyond STI levers. Based on some online perusing I've found the Cannondale Topstone Ultegra RX or RX 2 and Specialized Diverge Comp as viable options. I'm certainly not locked into those so other options would be appreciated but I know when this COVID-19 ordeal is beyond us I will likely be able to find those to test ride locally. I've never thought I'd spend this amount on a bike but I guess I'm looking in the $2K to 4K range.
Criteria:
Light - I don't own or have ever ridden anything under 23 lbs so I'm hoping to find a sub 20 lb bike. My touring bikes give me all the comfort I need but cutting about 10 lbs off the ride would the main reason for the purchase. I'm thinking carbon is a must to get to this weight range but am not opposed to aluminum at a similar weight.
Comfort
- as I age I like more height on the bars so help me out with something with higher stack height and upright positioning. I ride in the drops some but don't want a ton of hand pressure when riding on the top.
- I'm a fan of wide tires but some type of additional vibration reduction would be nice. Probably more on the bar/hands unless they are up high enough.
Utility - I know it defeats the weight criteria but the ability to add a rack for lighter touring or just extra gear is kind of a must. Fenders would be nice but probably not a deal breaker. Unless I'm touring or get caught in a shower I generally don't ride in the rain.
Quality - I want a bike the company will stand behind and I have access to parts/service. At 66 the number of years and miles I'll be putting on it shouldn't be an issue with the longevity of the wear and tear of most parts.

I would greatly appreciate any suggestions based on experiences with the couple I'm considering or what you may suggest. I have a 2004 Specialized Sequoia with Shimano 105 and find the components fine but if anyone feels Ultegra is well worth the upgrade please let me know also.
Thanks in advance for helping me find a ten pound lighter, wider tire version of my 84 Miyata 1000 :-)