VO2 Max for indoor cycling

For cycling vo2max you need a power meter, and the venu 2 does not support power meters, so no, you cannot get vo2max for indoor cycling.

It doesn't give you a VO2 Max while cycling indoors, but what cycling indoors with the right set up can have an impact on some of the metrics tracked by the Venu 2.  I have a Concept 2 Bike Erg and I connect to the ErgData app when cycling.  I've also linked my Concept 2 logbook to Garmin.  So, after I've cycled and save my workout to the Concept 2 Logbook, it automatically uploads to Garmin (including the Garmin app) with a ton of stats including my watts which then gets factored in to my Power Curve as shown on the Garmin app.  So, this essentially acts as a power meter for cycling.  While I can't see a specific cycling VO2 max for cycling, when I do an activity that triggers a VO2 max reading (like a 20 minute outdoor GPS  walk) it reflects an improved VO2 max.  Plus, for purposes of your Fitness Age, one of the stats in how often you vigorously exercise during the week.  Only exercises that generate a VO2 max reading factor into this.  So, if you do an outdoor GPS run, it will factor into that if your HR goes high enough.  But, doing an indoor HIIT workout will not, regardless if you've actually vigorously exercised according to your HR stats for that workout.  However, my indoor cycling workouts that get pushed to Garmin from Concept 2 DO count for this metric.

I'm not sure what indoor bike you have, but you may want to look into whether it can connect to Garmin.  You may already have a power meter and not know it.  Good luck.