Unity 2019.3 scale canvas with screensize causes canvas to jump sizes repeatedly

As the title says. I'm trying to work on a new canvas for my game, but for whatever reason, putting the canvas on fit screen size makes it jumpy. from small, normal and big. Which makes it impossible to properly do the UI. Now I know, I can just set it off that. only problem. then the canvas-sub game assets sizes don't work properly. Is there a way I can fix that? if not. is there a version above 2019.3 that doesn't have this problem?

 

I would check if this issue occurs in earlier releases, such as 2018.4 and 2019.2, because 2019.3 is currently in beta and perhaps it's a regression. If you're looking for a newer version than 2019.3, there is the 2020.1 alpha available, but alpha means even buggier than beta.

 

Hence why I am asking. Downgrading or upgrading a project might mess up the project. I can't downgrade to the 2018 version since I would have a lot to change (Above 2019.3)