Hi, if you are new to cycling or just getting back into it your Z2 plan sounds very good. As you likely know the most important thing is consistency, and one of the best way to be consistent is to have fun. For some people Z2 or doing things the “right way” is fun but others might need more intensity to have fun or at least some intensity on a periodic/weekly basis. If you know yourself and Z2 and watching youtube, netflix, music… is fun then the FREE version our app is perfect.
I would go to settings and enable auto-extend workout. Then I would just click on the quick start and start pedalling. Do a 5+ minute super easy warmup and then just press the plus button until you get to an intensity is just below the border of what feels medium. A better sign is right below the point where your breadth changes or roughly 65% of max heart rate. So this is free in our app and perfect. You don’t even need to know your FTP in this case. After you get a few weeks or a month into it you can take an FTP test or if you are in a little cycling shape now and a perfectionist you could start with a ramp test.
So you don’t need specific “workouts” you just need to spend time pedalling. Now from a free perspective if you decide you need a little more visual entertainment either Zwift for 25km/month for free or MyWhoosh (unlimited free) can add some variety to this, but personally I find our app and movies, documentaries and music the right type of entertainment for me.