I am a strava premium subscriber and use the fitness freshness graph produced by them. I have just started a training plan with Zwift but don’t have any way of comparing /quantifying riding and Racing IRL or even zwift racing. If my account synced both ways that would be ideal as zwift is only a portion of rhe riding I do given thst we don’t really have a winter to hide from in Queensland.
You might want to clarify what you’re talking about. You can’t import ride data in Zwift as there’s no where to review past rides apart from getting a basic list of dates and distances. Zwift syncs with Strava so all rides done on Zwift plus any outside rides can all be reviewed there. You can then analyze your combined rides on their various pages. That’s what I do is addition to having a Trainerroad account. I record all of my Zwift rides using Trainerroad running on my phone.