I agree this is not great. However, it has been reported before and the developers added a Visibility Panel in the Object properties tab. This contains the viewport visibility, show in renders, and selectability properties where you can attach drivers as expected.

Note that currently, the outliner 'viewport visibility' button doesn;t correctly shade the button purple if there's a driver attached.

i think the devs are working on a more complete resolution to this issue as part of the next major outliner change which will likely come in 2.81.

I tried on the visibility panel and wasn't able to add a driver to the "Selectable" box but I am able to add drivers to the other 2

I apologize. I thought you were talking about the viewport visibility option. I do not know if you can add a driver to selectability at all.

Its ok, although it was possible in 2.79, I used this to control the selection of meshes on rigs, so that way I wouldnt click in the mesh on accident while wanting to select the armature, and used a driver to control the selection if i ever wanted to edit the mesh, it was a big time saver than enabeling all the mesh objects that belonged to that rig, so instead of searching for one specific object or enabling all, I would use a bone as a switch/slider, so it was a 1 step thing for on and off

You might want to investigate using the new Edit >Lock object mode toggle. You can bind it to your quick menu so you can toggle it at will. It helps keep you in pose mode and prevents inadvertantly selecting the mesh.

Mmmm ill definitely look into that. my 3rd attempt at controlling this was by giving the mesh a custom property that enables and disables selection by either being 1 or 0, then add a driver to that property, but since im a nooby at coding i couldnt get it to work right