Check out what Brendan said - it’s 3 workouts for 3 weeks. I typically decrease interval length while increasing (slightly) overall time working. Between 18-21 minutes is good for most athletes like you, so that could be 4x5, 5x4, 6or7x3 etc. Lots of posts in the hard start VO2max interval thread about execution of this type of workout and block.
Re: endurance. You can if you want. Keep your volume about the same as it normally is. HOW you do that doesn’t matter as much. If you want to add time to your workout days, keep it really light, 55-60% and that’s fine. That keeps you off the bike a couple of days.
This is my third season now coaching @BCM so he’s giving you the down-low, but I’ve also posted this approach here a number of times. Note that there’s some nuance to the interval execution that’s been discussed elsewhere, primarily this thread.
From a strictly bike performance perspective, this is way too much. And during a VO2max block like this, I’d reduce this workout down quite a bit, maybe once a week and reduce the sets as well. This is a big, big upper body workout, man. With the block design you’re using, you’re not really resting at all. Just because you’re off the bike doesn’t mean you’re recovering if you’re doing this kind of load.
Again, that’s from a bike performance perspective only. If you have some other reason to train that much, then have at it, but recognize that it’s hurting your cycling because you’re not recovering enough.