I was expecting the responses to be more mixed. But pretty much the issues I see here confirms to me that Manjaro is not the winner. I think Endeavour is going to be the one I will install.

Snaps is too well controlled by Canonical and does have it's limits.

Flatpaks can be very secure, and works in most distros. It is one of my favorites.

AppImages are real easy, and is designed to work on most distros. The only problem is that many apps aren't current. So I don't recommend it unless an app provides it on their own sites. AppImages are often made by somebody else.