They have been using two old tplink wifi routers, flat network for employees and guest ...
I did install and configure new network build on unifi devices : cloud gateway ultra, ultra switch and 3 x U6+
Now, they have two separate networks {well, plus management vlan for all network devices} one for employees and one for guest with better coverage of wifi.
if you need some help or tips with your local network dont hesitate and ask ;-)