Depending on the rim a low spoke count carbon wheelset could be fine on training rides. The spokes only hold the hub in place on strong rims, you don't need them to make the wheel structurally rigid enough to keep the rim from deforming massively.

My normal training clinchers, the non-aero HEDs, are 18/24H.

A really strong rim doesn't need spokes to support your weight, and the few carbon rims I've held unlaced have been strong enough to support my weight sitting on them (carefully). Box section aluminum rims would start to flex so much I never put all my weight on them. In my case the rims I've had unlaced in my hands are Zipp 440, 340 (the predecessor to the 404 and 303), Reynolds DV46 tubulars, DV46 clinchers. Zipps were 24H (340s, 440s) and I had a 16H front 440. Reynolds were 16/20H for both clinchers and tubulars.

In the case of the Reynolds they were strong enough that I could ride or race while missing a spoke from either end. I popped a rear spoke on a clincher just as we started a 2.5 hour hilly group ride. I decided to keep going because my tire wasn't rubbing anything; wheel was fine. I popped a front spoke on a tubular during a race. I raced the rest of the race on a 15 spoke front wheel, and after experimenting with it on the hill and the 45+ mph descent, I decided it was strong enough for me to contest the sprint. I got 7th in the race.

15 spoke front wheel race: