How to deploy a WiFi network in the office on dd-wrt?

Question

Computer networks

There is a task to quickly deploy a network in an office that does not have a single forwarded copper. Area about 500m2, one floor.
I tend to use inexpensive wi-fi routers with dd-wrt firmware and the following network topology:
server <---> remote main wi-fi router in AP mode (several antennas, high speed) <---> simple routers in Repeater mode (Repeater bridge) in each room or as required.
There is practically no experience in building wireless networks, therefore:
1) Will I have many problems with such a solution? Of particular concern is the IP telephony system, which should be deployed over this network (asterisk + 15 subscribers).
2) Advise good hardware for the task: for the main router and for stupid repeaters.
We do not offer proprietary solutions, since in case of successful experience we plan to use similar systems for our customers.

Answer 1

Connect routers with cables better.

Answer 2

You didn't specify the number of clients.
Briefly, if more than 15-20 per point - there will be seams.
Clients are mobile, will they run from point to point?
Believe me, copper is better.

Answer 3

how did you do it in the end and what happened?