New Bike dilemma:

Hi everyone

After riding a Cannondale Supersix (105) for nearly 15 years, I want to make the change to electronic shifting, doing a bikefit and making proper miles/kilometers on a regular base again.
My budget window is 3xxx – 4xxx, looking for an allrounder bike – ‘aerofit but make it comfy enough for regular longer rides’.

FYI:
– 32 yo male, 1m70, 68kg
– enjoy doing 📈📉, love going hard on asphalt roads
– average rides: 50 – 120 km per trip (2-3 x/ week)
– yearly trip to French/Italian/Spanish altitude

Dilemma:
I came across the Cube Agree c62 Race
€ 3949 with Ultegra Di2, but the 2025-2026 Canyon line looks very tempting. Currently preferring Shimano over Sram – based on reviews and this community. My question to you guys:

* is the ultegra di2 remarkably better/ smoother than 105 di2?
* Is the Aeroad comfy enough, compared to Endurance or Ultimate?

Options
– Aeroad CF SLX 7 Di2
Shimano 105 Di2, DT Swiss ARC 1600
–Endurace CF SLX 8 Di2
Shimano Ultegra Di2, DT Swiss ERC 1600 Dicut

Thanks for your opinions and time!