Yes what VO2 power training does is to support an adaptation of your heart volume per beat. So pump more volume of blood per beat. This is very supportive for the climbing effort on low intensity. However it also triggers quite some fatigue which you want to avoid to ensure that you can train enough volume (long rides at Tempo) that triggers your endurance adaptation. In the end its an endurance race and not a hill climb race. So my training consists of min & max 1 VO2 TR per week any time during the lead up to the Taper weeks.
A bit late of a reply but I would agree to try to get as much long days in as possible, I feel personally a few 3-5h rides are really helpfull in improving my all day endurance and importantly if you are not used to those long rides it will show you where you get unconfortable (allthough what works for 5h may not be working after 8-10h).
If people have access to climbs it is really helpfull to actually climb in training, you use the muscles a slightly different way and what is comfortable on the flats may not be as comfortable on 8-10% inclines. I’m lucky enough that I have a few 10-12 Minute climbs near me where I can do shorter Threshold efforts and Hill repeats, and I can swing a few rides to a bigger mountain before the event (perks of living near the Alps).