Unfortunately this seems to be the software how it is. I have downloaded iPadOS 15 beta on my iPad Pro 9.7 and it does the same thing. There are no options in settings to change the size of the icons or make room for more with the “more” option. The display now looks ugly and there are huge gaps either side of the screen which should be used by icons or widgets. Have downgraded back to iOS 14 as I prefer the look. Hope apple reads this and addresses the issue. Not sure who thought it was a good idea in the first place.