Worth Buying a PS5 at the End of the Year?

I have a lot of games I need to get finished on my Playstation 4 but thinking about buying a PS5.

Here are some questions I have, simple as they are they got me wondering:

• Is it easy to transfer my PS4 saved data games over to the PS5, to my understanding it has backwards compatibility and is this on the basis that you if you login with your PSN network account every saved data including off the cloud should be there or is it separate transfer of all your game data onto the PS5?
• I have an external storage device, if I connect it into the PS5, will all my saved data on it also transfer over to the PS5?
• Will the internal storage videos that I have captured via the share button on the PS4 transfer over to my PS5 or will it start with a blank slate?
• If I have a subscription say a PS Plus on my account, will that also transfer over ot the PS5

The answers are probably obvious but I want to get confirmation

I know when I installed a game it would say I had a saved file on the cloud storage.