1. Visionaire Studio automatically scales the game up & down to fit the display resolution of the device the game is being played on. It retains the same aspect ratio, so if the display resolution of the device is not 16:9 in this case (based on your default game resolution) then it will probably have black bars visible.
Quick note #1: you should
never change the default game resolution once you have started development as it's not going to automatically scale your images, animations, way systems, interaction polygons, etc. down to the new resolution in the editor.
Quick note #2: you should also avoid the change resolution option in the export build section of the editor as it's not very reliable - same in regard to the convert to webp option.
2. I'm sorry, but I can't help you there. I would highly recommend that you join the VS discord server if you aren't already on it as the same question you've asked has been asked multiple times recently & answered too.
https://discord.gg/g5zFejW
Newbie
Imperator