Therefore I need suggestions for a Gromuter with internal routing (like the Ribble CGR) but biggerer tyres (like the Ribble Adventure) as I want fat tyres with mudguards or light knobblies on occasion.
Mounting points for stuff, mudguards and racks a necessity, dynamo goodness and thruaxles yaddayadda.
https://bikepacking.com/index/650b-gravel-bikes/ is a pretty comprehensive list to get you started