The one thing to be aware of when riding on zwift ( and this may depend on whether or not you use a smart trainer or static with power on crank : pedal system so I may be corrected by anyone on such a system ) is that in a power file analysed retrospectively, I find that I am making very few anaerobic efforts although my average power is high relative to ftp. Therefore as a fun way of training it has its uses but in terms of addressing limiters etc it is not particularly good in terms of specificity regardless of what you do in terms of racing etc. The training programmes in it are better for this. Hope this is useful btw I am now on the aero bike .