Question: "wireline broadband service" - you mean, I believe, DSL.
Reference FYI:
https://www.fcc.gov/general/types-broadband-connections
What ATT is doing is delivering internet service via a telephone line.
The line comes into your home and goes to a splitter (also called a filter). The splitter divides the incoming signals. One part goes into your telephone system. The other part goes to your network via a modem -router pair or perhaps a combination modem/router.
Either way, you should be able to configure your network as necessary for wired or wireless connectivity.
Modems and routers have wired connections via some combination of WAN and LAN ports. The modems and routers may or may not have wireless capability per se. So you will need to ensure that your modems and routers do indeed support wireless.