For dragging, in that case, can you try in the Help Vault to see if it’s a theme/plugin issue? And if your Obsidian installer is older, you might have to download and reinstall.
And, I see what you mean. I don’t see any obvious way to close it either. The only way (and same in this old thread) is to unload the Tags plugin in settings. I’ve never closed it, because I just keep those tabs open all the time.
I do set hotkeys to hide the right and left side panels. (Cmd-[ and Cmd-] for what it’s worth.)