That’s cool about the hotdesking! I only hotdesk the phones that my teams use when they work from home. In-office I use more of the “always logged-in” extension style you spoke about. Now back to your question. What ports have you picked to provision the phones? https://wiki.freepbx.org/display/FPG/System+Admin+-+Port+Management
With DHCP does your setup look like this?
What kind of router are you using? Can you please confirm that your router’s network has been set up correctly to use DHCP option 66?
Hopefully, I have given you some things to read to get you to where you want to go.
I provision my phones using this method.
I have provisioned phones using DHCP option 66. My recommendation is, if you’re not going to use Sangoma’s redirect server, in my opinion the easiest way, is to use the method I suggested above. In my opinion, it’s way easier than using Option 66 due to the less network config needed. It’s 1 less thing that can go wrong. Hope this helps. Please feel free to look me up if things don’t go well.