We have the possibility to change the size of the Canvas App in Power Apps Studio which is really great. But when we do that and then run the Model-Driven App and open the form on which we have embedded the Canvas App, the section can still be very large (long) compared to the resized Canvas App. This might be a configuration issue, but I have not managed to change the size of the Canvas App and then get the section to be the same size as the Canvas App.
I have added 3 Pictures. Two of them shows an example of when running a Model-Driven App and it shows the section is very long. One of them shows the Power Apps Studio. It shows that the size of the Canvas App is not that long.