Well deprecated may not be exactly the right word, but there's not a single word that is totally accurate. Maybe "sunsetting"? :P

That's essentially what deprecated means. It is discouraged to start new projects with it. It doesn't mean that it's dead, but we seem to always take it that way.

Deprecated implies "will stop being supported soon, so you should stop using it as soon as you can". Maintenance mode implies "will continue to be supported for critical things like security fixes, but won't get new features, so there is no hurry to stop using it if you are fine with it staying in its current form forever".

Actually deprecated implies a deprecation timeline, which can be on the order of years.

Python 2 was deprecated when Python 3 was released, but the timeline of transition was over 10+ years.

Django has deprecation timelines that last over 1.5 years.

In Enterprise, its often seen to have deprecation last 7 years.

During deprecation, only maintenance is performed. That is---security fixes.

The real difference between deprecation and "maintenance mode" is that the later is indefinite and implies continuation until profit-loss. AWSv2 isn't in maintenance mode, its deprecated. Eventually Amazon may stop offering it, and doesn't want you to start using it, but while its in operation that doesn't mean they won't close security holes in services that offer it.