One of the criticisms people have with containerizing their desktop apps is the "insane amount of space for their environment" that people think it requires. That's a direct quote from a reddit post on the topic from today.
Let's have a look
Today I'll compare two desktops, one will be
Flatpaks aren’t huge at all. This is a debunked myth. I can’t recommend reading this article enough.
The space isn’t taken up by one app. Its the platform dependency that takes up a bit of storage.
If you install one app is feels huge but the next one that depends on gtk or qt will be small.
Its the same think with desktops. If you go to a bare bones no GUI Linux system and install Firefox it would be a huge download.