Android Note taking apps for real time collaboration

Did you try Samsung Notes? It is fantastic! But it requires the other person also to be using a Samsung device and have a Samsung account. There's also Goodnotes on Android. It is being updated, so you might get the sync feature soon!
I am currently using it. It is a good. Except few operational issues- and there are plenty. But yes, it is good for collaboration. It is slow and that gets irritating. Notewise is actually good but there are two issues there: recurring monthly payments and inability to share folders.
Go to web and use figjam, you'll forget anything else exists
Oh I wish they have android app. I am a heavy user with the need of pdf annotation
Google keep, Google tasks gets the job done for me
It is good but lacks stylus support. Can't upload and annotate pdf
Been using Google Keep for years now
I wish it had stylus support.
Standard Notes - Cross-platform note taking app. Which i been using it for 2+ years. Unfortunately no real-time collaboration.

But I've found a couple of apps that might fit what you're looking for:

* Turtl (https://turtlapp.com/): This open-source app allows you to share content and features client-side encryption. However, it doesn't seem to offer real-time functionality. The only drawback I noticed is that you need to download the app to access it.
* CryptPad (https://cryptpad.fr/): I'd recommend this one. It's also open-source and uses zero-knowledge encryption, which is a big plus. You can share and edit notes in real-time, and it also offers additional features like sheets and other text views. Both apps are completely free, with optional paid plans if you need more features.
I checked out Turtl and it seems archaic. No updates since long time. Also, pdf annotation is absent. In this day and age, it just doesn't make sense really. I am surprised by the lack of good reliable options.