I haven't been paying attention to the bikes that Trek is making these days, but maybe one of the new lines is really a Madone with another name. Since you loved the Madone before, I would ask someone who sells Treks (hopefully there's a good LBS near you that can help) what the successor to the Madone is.
FWIW, I am similar to you in the way I use a road bike -- long rides, not competitive, I used to do some centuries but these days keep things under 70 miles, I don't hate climbing but I'm slow going up hill and it will always be way in order to prevent asthma from becoming a problem when things get steep. My current bike is a mid-range Madone and I'm happy with it. The carbon frame does absorb road vibrations better than my old aluminum frame with carbon fork. Most importantly, my current bike is a good fit for me, better than my old bike was. The main drawback for the Madone is that I have to be more careful in handling the bike (putting it into the car, leaning it against something when I stop for a break) than I was with the old one because the carbon frame is less durable and more prone to cracks from impacts. I am nowhere near wanting to replace it, but if I had to I would look into steel and titanium frames in addition to carbon.
To make the hills less difficult, you'll want to look at gearing. I don't know enough about it to provide good advice, but I made sure the compact double on the current bike was sufficient to get me up the hills where I typically ride. The easiest gear is comparable to the granny gear on my old bike, which had a triple chain ring.
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles