Make sure it’s not filtered to just your time zone and/or only group rides or races etc. You need to have it not filtering anything to see full list of options.

It's great for getting a ride in when outside isn't workable. It just isn't practical for me to ride outside before work given my circumstances but Zwift makes it reasonable for me to get an hour in a few mornings a week.

I do wish there were more rides at various levels to jump in on. The time passes faster for me if I've got riding with a pack to occupy me a little but there aren't always groups available or at the level you might be looking for.

It would be useful if there were groups at the various levels to jump into it at any time. For my morning time slot there's a day or two where I have one or two to choose from but realistically most of the week I have at best one ride available when I need to start or I'm riding by myself. Fridays the rides either start too early or too late and I'm getting up as early as I am going to with a workday in front of me.

What internet speed is needed for zwift? Thinking of starting with zwift but my internet is pretty bad

Honestly, I don't know. My connection is fast, but most of it runs locally on your CPU/GPU

I have pretty awful DSL and I have not had any issues with running Zwift. My bike and iPad are setup pretty far from my router as well.