looking for advice on silicon seal around shower drain

Hi there

The silicon around our shower drain was looking like it was coming away from the edges, so I decided to take it out and replace it. I discovered a bit more silicon than I thought, and that there is quite a deep gap around the plug (about 2 inches).

I have included some pictures, I would like to get some advice on whether or not I just replace the silicon, or is there a more permanent solution to sealing the gap around the drain?