I find the Allan/Coggan training rides to be quite useful to sort that out, Ignoto. THey basically say "go do a 2-3 hour ride at tempo, and do your 2x20/6x6/sprints at the end". 2-3 hours might be a bunch ride, which keeps it interesting, and maybe you do your intervals when you ride home from the coffee shop, or on the way to the ride. Worst case, maybe you jump on the rollers for 45 minutes when you get the bike home?
We certainly need to liberate ourselves from the idol of HIIT as being the only way to skin the cat. Yes, it is the best way to develop, but you might not want to obsessively restrict yourself to only being on the rivet after a warmup for 45 minutes before a cooldown. Maybe you could find a nice loop that you can safely hammer out 90% power that you visit after your rides? I know a MTB guy who lives in the mountains and can do 10 minute intervals on a few different climbs, and recovers at 80kmh going back to the bottom
bit of a stressful recovery, but that's cycling