I have the same problem.
Just isntalled Project client and View –> Task Board is missing.
The license is the right one: Microsoft Project Online Desktop Client.
Version inatalled is 1905.
If anyone can help…
Alfredo, that’s the same version I have and all works. Are you connected to Project Online or to Computer Project Server account? Connection to Project Server (at least 2016 and earlier) won’t show the task board.