I bought Garmin fenix 6x pro before a week and my VO2 max didn't changed after 4 running activities... Could you find a solution for my problem?
To get a cycling VO2 max you need to be using a power meter during the activity. This article has some good information that should help you get your VO2 max. What is the VO2 Max. Estimate Feature on My Garmin Device?