Difference between Multi-Account Containers extension, Facebook Container extension, and the built-in Container Tabs features?

[lgcvsa]

Can someone please explain to me why there are three different codebases that all seem to be doing the same thing in Firefox, but slightly differently?

First there is the Facebook Container extension, which it seems has no been updated in 2.5 years.

Then there is the Container Tabs feature built-in to Firefox.

Then there is the Multi-Account Containers extension.

It seems to me that these are all somewhat redundant and overlapping efforts, and that it very confusing for users. Are all of these codebases actually recommended? Are some of the deprecated? If so, why aren't they marked as such and/or made unavailable? Is there only one of these that I should be using? Can I or should I be using them all at the same time?