GTAV's multiplayer made by the community it's out.
https://forum.gtanet.work/index.php?forums/news-and-updates.2/
The sync it's still in progress but it's one of the firsts MPs that came out this year. Now, we need to sit and wait for Take2 do or don't do something.
Personal opinion
Take2 want to make us pay GTAV twice. Their GTA Online is terrible (i mean the idea). The community need to have more. Make own mods and play as we like, but Take2 wanted to make it difficult for us and bring a lot of hate for them (well deserved hate).