Top ones come out fairly easily usually without a special tool.
You’re better off making or getting a bottom joint tool made.
Here’s one I made from steel offcuts I had. As you can see they can be very tough to remove so make the top piece from something substantial or braced- channel would be better as a lot more resistant to bending.
The joints regularly pop out of their sockets so need welding to remove the whole joint. The heat from the weld probably helps loosen things too.
Not pictured is a section of the correct sized steel tubing which the tool sits on to keep things centred, and that the joint can be pulled through