If you have; speed, cadence and power meter in use; no.
If you are missing a power meter or speed (not 100% sure if cadence is needed, but I think it is); yes.
Then only way to get vo2 is to use "Run" -workout (treadmill5/trailrun are no good), outside, with hr on and do at least 2 separate 20min long runs.
Power meter not have.On cycling ride have on all Fenix 5x sensors :speed ,HR,Distance height etc etc
You need both a power meter and heart rate to get VO2Max from cycling. As it sounds like you don't have a power meter, you won't get VO2Max updates.Interestingly I cycled to Parkrun yesterday morning and had my Stryd footpad on my shoe and when I checked Garmin Connect last night, for the first time ever, I have a Vo2 max reading for cycling. I don't know if Garmin have changed something or whether the Stryd can be used for cycling but something has given me a Vo2 that I didn't have before. I did have my HRM-Tri chest strap on but I have done that before when cycling.