I was able to set up a PAN between my laptop and my Jolla phone only after uncommenting

DisablePlugins = network

in /etc/bluetooth/main.conf on the telephone, and then starting pand with the appropriate options on both sides (phone and laptop)

I can now ssh into the phone over the bluetooth link.

Of course bridging and dhcp would be the icing on the cake, but now that I have a connection I should be able to proceed in much the same way as with an USB link and use the phone as a gateway to the internet.