Maximum slope in the description of the route

I got back on the bike after a long time and therefore I have little / no training.
The problem is how to choose the path since the description lacks the maximum slope that can be found … the difference in height in the description indicates little.
I also like to vary the path so as not to be too monotonous but often, especially now that I’m not trained, I always end up doing the same.

Welcome! You’ll find a great list of all the Zwift routes, including gradients at Complete Master List of All Zwift Course Routes | Zwift Insider

There’s an extremely varied selection available.

Thank you.
I saw however it starts to get complicated when you enter the app and you have to choose the path.
It would be useful in the app, in addition to the distance of the route and the elevation, if there was also the percentage of the maximum slope so one can explore more routes based also on one’s training level.
Yesterday, for example, I did the Flatland Loop (Makuri Island) where there are peaks at 6% but in the description it said flat.

You don’t have to do manual turns. If you pick the route that you want to ride from the home screen, then Zwift will automatically route you. Those pop-up directional choices at junctions are only if you want to go on a detour. Just don’t press any manual turn buttons and you’ll stay on your selected route.

For each route, check out the detailed info if you click on the route name at that Zwift Insider link. That will show you the route profile, among other things. As you saw, while Flatland Loop doesn’t include any mountains, it’s not pan-flat.

Also remember, you can always do a U turn or set trainer difficulty lower (or zero) or end and restart a ride based on how you feel.
One of the best things about Zwift is you never have to ride home.

If the goal is really to avoid grades, set your difficulty super low and the world will feel flat. It still takes the same watts to do any ride but it will feel flatter.