How much do you value your time? The reason I ask is that it makes sense to invest in a direct drive turbo trainer, and a subscription to a cycling app or training program. Personally I race on Zwift once per week in early winter, and probably 2 - 3 times as it gets colder and I do less outside. A Zwift race, in a competetive series like ZRL (Zwift Racing League) will be 45mins - 1 hour max effort, depeding on the course, it could be a series of max efforts followed by short recovery, or it may be a constant FTP level effort. Last season, my FTP went from 330w to 350w through zwift racing. 90 minutes is about right for warmup, race and recovery.
For your one of the other sessions, you could do a structured program or join a training group ride at a set w/kg, there is a social element to these rides
For the final session, I would probably look at another race, but go for a slightly less intense series. The Crit City races tend to be easier
Not interested in Zwift, the trainer road have some great ftp building programs
I will look in to the direct drive trainers and cycling apps, I don’t really know what they cost but I certainly do value my time.