By default Firefox puts spacers either side of its URL bar, is that what you mean? Just remove them

But on the plus side, this idiot is 34.76 billion poorer

PC with 2 NICs would solve this surely? 1 port to the building for Internet, the other to your offline router which connects to your headset wirelessly

Now you get to do it again but this time to the VPN users that thought they were above your antics

But makes coffee shop wifi inherently more risky