Base or build? Build HV is very doable as the extra volume during the week is Z2 stuff. Base is where the difficulty of HV lies because is 5 days out of 7 doing sweetspot and 4 of those 5 are 2hr sessions. Can you handle 12 weeks of 4 days of 2hr intense training sessions is what you should ask yourself. It’s psychologically very draining and only unless you have a definitive goal for your training will you find it not a struggle to get on the trainer. I’m not saying this to put you off but to make sure you’re prepared. Adding Z2 workouts around a MV plan is another option and what I would (actually am) go for if I have no goal. From personal experience, HV gives you way too much time of self questioning when you have no actual goal. It takes a lot of effort and you begin to question if it’s worth it. Well yes, if I knew I was racing in the season and I knew everything was going to be open again then I could convince myself I’m training for a reason.
All that said, HV will boost your FTP like no other if you recover well. And the increased time on the bike reduces your TTE considerably. You will start to notice that it takes a lot to break you. It just makes you a stronger cyclist and it becomes obvious how stronger you are when you ride with other strong groups. I would recommend anyone looking become a stronger cyclist does a HV plan at some point but you have to make preparations around your training that you wouldn’t normally because it’s a serious amount of training.