In the spirit of recommend what you have – I second the previous-gen Synapse carbon.
My first one did 40,000kms as a winter bike and never missed a beat. Internal cables/hoses (not fully integrated at the bars) with no issues changing headset bearings. I modified the bb guide and rear stop to run a full-length gear outer.
The ride was smooth as silk, fitted 30s with guards, and I ran a screw-together BB in the BB30a shell.
Only sold it because it was starting to look a bit tatty and I replaced it with… another one. Built up with 12spd Di2 this time. The latest-gen Synapses are quasi gravel bikes and all the integrated lights gubbins put me off so I hunted down a NOS older one.