Wlork Yes, you will only need to manually remove the extensions that are not compatible with 2.x beforehand. You can do this without using SSH.
One more thing: if you set now Minimum Stability to Dev in the Extension Manager, you can update to 2.x. (not recommend) Of course, you will still need to remove extensions one by one if they don’t have a 2.x release yet.
So, you either need to wait until all the extensions you’re using are updated for 2.x, or find suitable alternatives. To speed up the update process for extensions that are critical to you, you can contact the developer and consider making a donation, or ask another developer to take on the update.
I believe the transition to version 2.x will be quite straightforward.