I don't see anything in this document requiring a SBC for hot desking. That being said, depending on the environment for which you've not provided any information on, a SBC may be required or recommended as far as keeping the phones themselves in a supported state, regardless if hotdesking is used or not
when I go to advance then hotdesking and add it will not let me do anything without sbc.
hence the question if there is a way around it.
the environment is hosted 3cx Pro v18 update5 license.