I am in a very similar boat… I am looking to get a new bike this winter and the comfort is primordial for me. And please don´t get me wrong, I ride for many years and play a lot with all the contact points and factors of comfort in play - tubeless tires with right pressure, the best sadlle I could find (Bontrager Aeolus), carbon handlebars from 3T, Speedplay pedals…got it all, except carbon cranks (those makes a difference when you are standing while riding on a rough surface, I got Campy Chorus carbon, but actualy I am on alu + powermeter from Zwatt - so FSA alu body)
And boy there is a huge difference in different frames and mainly forks! I rode on a hars alu frame and gave it back after 30 miles - never more, than classic steel, different carbons and now I am on a titanium frame and I had to replace (technical reasons) fork from full carbon to carb+alu steerer - what a difference! Suddenly the front end is much harsher ride
So just like you, I really don´t want to hear advises to get an endurance bike, hack no, I want a racy position, this is not my problem. But I know very well how the frame + fork can play in your performance when you ride for more than 2 hours. And I am quite bitterly surprised by the actual switch in the latest generation road bikes direction. I was happy big players understood the importance of a smooth ride on the race bike - really not important for a crit racer, but when your focus is big and hard hilly rides on a mix of terrain (we don´t live in a perfect world), a firm frame just batters your body and you loose precious energy. A smooth bike preserves it, delivers you more fresh on the last parts and boy that plays a huge role after 5 or 7 hours!
SL7? No thanks, I am disappointed here, I was expecting the same smooth ride as SL6 with an aero touch, but their focus was stiffness - for me I don´t get it. No more super stiff Venge, so to justify it´s annihilation, we are going to give to our sponsored racers a stiffer Tarmac And we can´t provide our marketing department with big savings aero numbers, so we prefer to make new wheels tubeless incompatible
Sooooo… as TCR looks really nice, but not fully hidden cables (I admit I just love the looks) and seems quite stiff, what else?
There is still Canyon Ultimate - not fully hidden cables, but super aero and really comfortable. But nothing on stock, speculations about a new generation in sight just after the new Ultimate, but who knows?
Bianchi Oltre - apparently a very nice bike, some smoothness thanks to Countrevail, but less comfy than Ultimate…
Orbea Orca OMX looks really nice, not so comfy as a Ultimate neither it appears…
Cannondale SuperSix EVO - honestly starts to look realy interesting in my eyes… when you get the integrated cockpit it looks super slick, handling is on par with Tarmac, the question mark remains for me the comfort - reviews are a bit contradictory here… but seems as a very good allrounder… I would definitely like to test ride it…
Not easy to make a right choice, right?