Garmin/zwift/Strava data issues

Hello guys!

Winter has come to the canadian north and as I am not yet fanatical enough to ride in deep snow, I set up a pretty good indoor riding room which is made of: -Tacx flux smart bought last year -Apple TV with Zwift connected to an old, unused 32 inch TV I had laying around -Wahoo tickr which was the only heart rate strap sold at my LBS -Garmin Fenix 5 sports watch, which I use to compile all my training data (bike riding and jogging in the summer, hiking, even long walks with the dog). The Garmin app takes all my training data so that I can see my progress, VO2 Max and other data that motivates me to get better. -My bike!

For right now I ride on Zwift. All those components are well connected between them and the data is uploaded to my Strava account (free, not premium) who then sends it to my Garmin account. The only things that the Garmin app does not calculate from a ride are intensive minutes and training effect, which make me sad because it gave helped me a lot with motivation last summer. I understand that since I have a heart rate monitor and I am not moving (no need for GPS), I don’t really need my watch but I liked seeing those graphs getting better and better number.

Any input on this problem?

Would buying a Garmin heart strap help with those issues??

Thanks all!