I have a TP account, so I watch my CTL, I do many different things, not just cycling. I record them all, skiing, running, hiking, gym, cycling indoor, outdoor. I can tell I'm fit, have more ability and recover faster if my CTL is higher than if it's lower, But getting precise as to what it means I'll be best at, I don't think so. I take it as a very general fitness number. I know I suck if I'm much under 50 and will have a good day if I'm in the high 60's, no matter what I do, as long as I'm reasonably recovered, i.e. my TSB is 0-10. Otherwise, I know I'll do best at what I've been working hardest at, whichever discipline. I'm fine with that.
It's really not about those sorts of numbers. To get more precise, I look to my results. Was I able to ski 20,000' before I got tired? Was our hiking uphill VAM anywhere near 400? I hike with my wife, but I carry a pack, she doesn't. Did we average over 14 on that hilly tandem ride? YMMV. But I think that's rather what the OP is talking about. We're currently training for our annual 10-day backpack in the Cascades. Been doing that for about 45 years. I'm having to admit that it's getting toward the "maybe" end of the spectrum. Training for that, we've found our best results came from doing a hard tandem ride on Sunday, day hike on Monday, then a mix of day rides, strength training, and running before the next weekend. Tandeming is killer work for backpacking, oddly enough. If you've ever ridden a tandem with your SO, you'll understand. I think that this is rather what the OP is talking about. It's not obvious, one has to experiment. CTL is a vague guide.
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Results matter