1. When the block is selected, viewport changes when any part of the block is outside of the view. This is mostly visible when selecting images that are partly outside of the viewport. No view change should happen here since users are irritated when something changes outside of their control. Simply disable this and the editing flow will be improved a lot.
2. Galleries: move new image upload button to the block editor toolbar instead of having this at the bottom of galleries. It shifts the viewport the most and having this outside of the toolbar also doesn't make sense. Bonus bug: editing single image in gallery opens an overlay with editing options you cannot exit. Selecting the X button removes the image and doesn't close the editing options and there is no way of exiting without selecting another image.

Fixing this should be pretty simple and would also make the editing experience a lot smoother.