I am, as you probably know, 77. My experience is that when the going gets weird, the weird get going. The others are history. The older I get, the more important it has become to train to a schedule, not just ride my bike Otherwise it soon becomes otherwise, and I don't want that. I like the feeling of being able to do whatever I want. I never grew up and don't intend to start now. I understand the Buddhist principle of right wanting very well, so I'm careful to only want things I can have - with enough care and work. I know my wife and I can't go touring in the mountains on our tandem anymore. We just can't make enough power and that's that.
I've become a slave to TrainingPeaks. I plan my rides and workouts a couple weeks in advance, using the CTL and TSB tools which TP provides. I ramp it up and ease it off as it pleases me and suits my objectives. Yes, I have objectives. Without them, I don't think I'd try hard enough to keep this old man moving up the road.
Trying to answer the OP's questions as if there were any, throw out all your history. Just forget it. Only look to the future. It's a scientific expedition into the unknown. Figure it out. Plan one week one way, another week another way. See what works. I just took 3 days completely off after a 10-day taper before an event ride, which I finished and finished with a decent pedaling time, though I took a lot of long rests and was probably 2.5 hours longer elapsed than what I used to do. But it was really hot and I really sucked on the 3500' pass climb in the heat. I was also undertrained because this spring was very wet even for the PNW and the snow levels crazy low so we couldn't go hiking in the mountains, which was always my secret weapon. Nothing like gong uphill with a heavy pack for a few hours with a steady zone 1 HR. Fixes my legs right up. The event was this past Thursday, and tomorrow, Sunday, my wife and I are heading for the mountains for an 3-day backpack. My legs aren't going to like it, but whaddya do. The alternative is unacceptable.
A schedule that's been working for me:
Sunday - 4 hour hilly ride, more or less, all the zones except Z1, hammer the hills.
Monday: - 30' Z1
Tuesday - 1-2 hr. strict moderate ride, constant power or just 30' Z1 if still trashed, 1 hour weights
Wednesday - 1.5 hr. moderate ride, not strict
Thursday - repeat of Tuesday, different lifts
Friday - 30' Z1
Saturday - off
Alternatively, hike several hours in the mountains on Monday, then Tuesday 30' Z1, no gym, not necessary.
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