If I only had one bike, it would be a cx bike with a rear mech hanger that I’d run single speed for races with a tensioner for avoidance of rear mech mash ups and occasionally ‘1x something’ for long rides. But would probably keep as SS most of the time. And I’m saying that despite doing most rides in Sheffield/Peak District. Took a few tries to find right compromise for both off road climbs and on road flats, but do-able.
dunno if you watched the US CX Nationals but (SPOILER) Hyde was really lucky. Ripped his rear mech off on an off-camber crash on the final stages of the final lap, he only had to run up one steep slope which allowed him to jump on and freewheel across the line. Another 100m and he’d have lost it. Glad it’s not only my SuperX that sheds mechs and hangers!