Yeah - I am actually starting to think Zwift have over - done it a bit with regards how much benefit you get from being in a group vs not. What I don't get is that even the guy on the front of the group doesn't have to be doing anywhere near the watts of a solo rider trying to break away or catch the group - that's how it seems anyway.
That's not to take anything away from your ride - you did it where it counted!
This is what I saw last week in the World Trials race. I was cruising in a pack of at least 40+ riders at over 50kph for ages. I can't even hit that speed when on my own or in a small group. Lots of PBs in that ride so definitely a massive advantage in Zwift when in large groups on flat courses.
The 'power up' game things also give a big boost, albeit short lived. On the hills tonight I had a 'feather' power. I was on a 11% section, doing 9kph at about 240 watts. Hit the power up, and with no extra effort my speed shot up to 12kph and the Pro recorded watts of 330 (as it just matches watts to speed of the terrain). I flew past loads of guys who had only just easily rode past me. I bet I gained 20 seconds on that section.
In races the power ups are sometimes banned, but not all races. This causes some riders to get annoyed as some play the game of trying to get the aero power up and take it into races. This power gives a huge advantage apparently during the final sprint and can be the difference between winning and losing a race.