Security of MESH WiFi

I am considering to install a Mesh "Nighthawk AX1800 (MK63)" in my small business. We have a network with about 15 users, voip, server and a firewall.

My consultant is guarding me about using a mesh system as WiFi access point, he says that they are very vulnerable to attacks and they will make the whole network very unsecure and exposed.
Is it true? What can I answer him?