This. Almost by definition, if you do 6x3 min intervals (e.g. Kaiser) at your max capability (same average power for each interval), you’ll be riding at VO2 max.
That might be, maybe, 112-115% for you indoors? You can determine by trial and error.
Nice work on the outdoor intervals! 117% average is a good number, and they are pretty consistent. Is your outdoor FTP higher than indoor?