How many hours/week are you riding? There are basically 2 approaches, hence the dichotomy you observe. 12 hours and up, 80/20 is common. 10 hours and under, it's more trad, sweet spot, some VO2max, some Z2. Thing is, at under 12 hours it's hard to get enough high end with 80/20 - understanding that it's not 80/20 in terms of time-in-zone, but rather workout days, so 4 Z1-2 days, 1 Z5 day. One does see a lot of recs for making that time-in-zone, but as you saw, that's way too much time in the high end. Obviously you're not going to spend as much time doing the Z5 as you do on a Z2 ride, so getting fit means a LOTTA time on the bike. I tried Polarized one winter, but I just couldn't put in the hours. Winter in the PNW means a lot of time indoors, and I just couldn't ride my rollers for 2-3 hours at a sitting. Ugh.
See this study with Stephen Seiler, the guy who noticed and popularized Polarized training:
https://www.researchgate.net/publica...nsity_Analysis
If you aren't familiar with the European 3 zone system, it's simple: Z1 is below VT1, Z3 is above VT2, Z2 is between. Some call Z2 in that system "junk miles" and you see that Polarized training avoids it for the most part. Which is another reason I couldn't manage doing Polarized. I'm not a really strong rider and just couldn't go out for long rides in hilly terrain and stay in Z1. (3 zone system).