If you had been using the 8 minute test to gauge FTP, these 6 minutes would be brutally hard.
Don’t get discouraged by some of these workouts in the build, as I see them as the absolute best case scenario if you can do them and that your FTP setting is probably too low if you finish all of the intervals without a little bit of power drop. I’ve often seen it suggested that if you aren’t punished in the later intervals that you aren’t really getting that VO2 MAX type of effort, but just a hard effort.