I don't run 10, but did find this. Maybe an answer is there some where.
https://www.isunshare.com/windows-10/change-local-storage-settings-for-flash-player-in-windows-10.html
Edit, I watched the video and I believe the reason for selecting small icons is only to keep you from having to scroll down the page. Go Figure.
Other information. I run 7 but just recently updated Firefox to 64. Lo and behold, I had to run down older storage folders for my favorites and bookmarks, they all just disappeared in the new version. Even on 62 that I had been running, I noticed problems with flash permissions.
I am going to call it a battery on the left side of the address bar, If you mouse over it , it will say manage plugins. I visit a web site(POGO) almost everyday that still uses a lot of flash. If that battery is red when visiting a page, flash will not run. Allow it on that page and the next page in will not allow it until you allow, it will happen on every page you try to load. When you allow, it will turn the battery black and you will be good to go. They are changing most of their content to HTML5, but the main pages still use flash. A lot of people(I suspect are running 10) are having problems on the site.
I know flash is self contained in Edge, but most browsers, OS's and sites are moving away from flash, either not allowing it to run or blocking it from running. As I don't/won't run 10, it could very well be a Microsoft update and is causing the problem. I did read that back in 2015 they had to patch 10 as the last update was blocking flash from running
I think the only reason for mentioning the above, is to give you some sort of an idea of some of the strange chit that is going on lately with Operation Systems and browsers, possibility to move everyone away from flash earlier then the end of 2020.