Click on the large gear button, then click on "Info." Check the "Launch at login" checkbox.
You can swipe right to edit it and swipe left to delete it. On Mac OS, it's also possible to right-click on the address entry and select what you need.
It gets updated every day on the backend.
You should install SSH/VNC clients that support being opened by ssh:// and vnc:// URIs, such Termius and RealVNC.
Synchronization happens automatically after you make some changes. There's no need to do it manually.
Sorry to hear that. Yes, you can request a refund. Follow the instructions on the Apple website.
You can use the feedback page or ask a question in telegram chat.