I can get to this setting page in my settings (screenshot attached). This is on a PC with I7 processor and the Zoom app updated to 5.10. But I can not click on any of the backgrounds or blur. When I click on them nothing happens. As you can see I also uploaded a background. No matter what I click on it just stays selected on None. I can change the options at the bottom. But blur nor any of the backgrounds are clickable.
I also attached a screenshot of my website settings. It clearly shows that backgrounds are enabled.