The Core Fighters patch broke the Ranked Search. Since Ranked is the only Online mode available, there is no way to find people. It will search for 2 seconds then tell you no one was found, and using throwdowns in Training/Arcade also does just endless searching. This has been verified with people who were able to connect pre-patch and unable to post-patch. I left a comment on the DOA FB page which said they forwarded the report over. I was hoping it was because the steam servers weren't synchronized yet, but sounds like that wasn't the case and it indeed is a bug issue with the patch.
As for Lobbies. Lobbies are not coming to the PC version of DOA5. Ever. No one should expect them to add it. However, those who do want to play online can find resources out there to help them out. There's the DOA Discord channel players are using to set up matches, there's the use of the Rank filter to find your friend who you want to play with, there's the use of automatic Steam or Twitch broadcasting. Basically, a "lobby" like experience can be set up if one so wants to. Is it a good replacement for an official "Lobby" mode? No, I don't think so, but it helps using other existing tools to mitigate the problems people are having with playing with friends.
I find more [5] and [4] connections on Steam than I ever did on PSN, and those [5] connections play practically at 60 fps. End Result: I have more fun on the PC version than my PS4 version.