Bro if u have an M-series phone, then Samsung Notes is just trash. It's accessible only from ur phone. Just use Google Keep if u have M series phone. If u have an A or S series, then u can only copy and paste. No other way.
I use windows. So onenote can a better option. But again, I have my Gmail account which is primary so Keep is not going anywhere. Also, I have a Note. I have to just install Samsung notes in my PC to access them. I am planning to use Onenote but then I have to sacrifice Screen off memo in Note phone.
In Note series, they do give us the option to sync notes to Onenote but I checked, they are going to Sticky notes and not in actual Notebooks that I made in onenote. And sticky notes can't be organized unlike other notes in onenote. This is a bummer for me. In my frank opinion, onenote is way ahead of keep. For now, I will stick with onenote due to close bonding between Samsung and Microsoft. Who knows when they will release an update and make us happy.