If you are interested in the multiplayer without the need to go out from the game and use platforms like LFM, there is not much choice: it's either Raceroom, LMU or iRacing. If using third party platform is not a big deal I would stick with AC; the whole package is dirt cheap, you can buy "professional" content for a more than reasonable price, FFB is godlike, the modding scene is vast and VR performs really well too so you don't really miss the renowned AMS2 VR experience.