The most active multiplayer Doom port is Zandronum, using the Doomseeker server browser to join games. Mac support may be a bit flaky, but I think it currently works (join the Discord for help).
I've always much preferred Zandronum over Zdaemon because it's open source and it has much more advanced mod capabilities (with much more Zdoom/Gzdoom mod support than Zdaemon), supporting mods adding game modes like the PVE Invasion mode.
https://zandronum.com/ - get the software, join the discord
https://doomlist.net/ - see active servers