Edited for clarity:
For best results you should use the hub in modem mode, and the mesh system in router mode. If you need more ethernet ports than the mesh system allows, just buy a fifteen quid gigabit ethernet unmanaged switch and put that downstream of the primary mesh unit.
But if that doesn't suit you then you can configure most mesh systems in "access point" mode, and leave the hub in router mode which gives you the mesh system's wifi, but network control by the hub's router. You'll need to manually turn off the hub's wifi as well to avoid conflicts.
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