@PitaJ How much work do you think would be involved in updating the import plugin to support NodeBB v2.3? I may well be willing to contribute some time and/or money to this if it's feasible.

I'm wondering the same thing. The most recent discussion of importing seems to be from 5 years ago. And import plugins appear to be abandoned and no longer supported.

As far as I can tell, there is currently no practical way to migrate to NodeBB.