In all JetBrains IDEs I've used (CLion, IDEA, WebStorm, DataGrip and GoLand) the IDE displays complete suggestions of symbols that are not currently imported in scope and accepting the suggestion, sometimes, will automatically import the symbol for you.
In PyCharm, you'll only get suggestions for symbols available in the current scope, even pressing Ctrl+Space will hint "No suggestions". The weird thing though is that if you ask for PyCharm to autocomplete & auto-import using Ctrl+Space+Space it will complete the typed thing with its best match even if it's not imported, in which case it will even auto-generate an import statement. (The Ctrl+Space+Space thing is discussed in here)
Using Ctrl+Space+Space does makes it a little bit better than having to type the full symbol, wait for it to be marked in red and then using Context Actions to import the symbol. Though it does require you to remember and hit the Keyboard Shortcut and it does not offer a visual list displaying your autocomplete options so it's impossible to know for sure what you will get with it until you do it.
This issue is present since 2017 for me, though I decided to post it here since it still annoys me a good deal.