Will a repeater fix a weak signal?
A repeater can help with a simple need but may reduce available capacity. For sustained workloads, assess access-point placement and wired connections instead.
Do we need a different internet provider?
First compare wired and wireless performance. The cause may be radio interference, the local network or the external connection.
Can visitors have a separate network?
If supported by the equipment, guest access and isolation can be configured. Specific restrictions are agreed with the network owner.
How many access points does an office need?
Floor area alone does not determine the count: walls, interference, active clients and applications matter. A plan and workload are needed; an advertised range does not replace design.