Auto Stepclimb?

Yes, there is a way. Not via the Infinite Flight app, but via a third party app called In-Flight Assistant.

The app has a (paid) feature that allows you to automate climbs (VNAV) just like you said. By setting altitudes to different waypoints.

Unfortunately, this feature has been buggy for a while, but the good news is it will be fixed (hopefully) with 23.2. With release of this update right around the corner, I’m sure you can download and utilize this feature before your flight.

For more info, check their thread out.

If you don’t want to pay, that’s a different story, but it certainly would have been nice if the first 3 replies mentioned this app.