Or, set it up like how you want it to open as (all folders collapsed),
then save that as a workspace.
Check the workspace’s keyboard shortcut (Go->Workspaces)
Hit that shortcut and it should return to the state it was saved in.
Note that Workspaces remember what databases you have open and closed and will open those that are closed. I run with all my active DBs open so my workspaces are just switching which DB is forward and which monitor window it’s in, another great feature of workspaces if you have multiple monitors.