Im Working with Phones and tablets - and there are some little things i’ll tell you^^
I develope in 16/9 because at 16/10 a bit will be cropped at the sides - its important fpr GUI and HUD and Stuff like this.
In my experiences the Phones are running faster in may cases - because of the resolution differences - more pixel to render etc. - keep this in mind somewhere.
Objects are placed and resolution is set automatically to the devices native one. so there is no reason to worry
Hope this helps a bit - if not, please ask a litte more detailed - happy game crafting