What’s better competitively for gt3 LMU or Iracing?

I want to get into proper sims and I love to race gt3 but I don’t know which sim to. I’ve heard great things about both and currently own lmu and have played it for a few days now. But if I want to progress and potentially brand out and join teams or even events it seems like iracing is the way to go. But, that has a big cost with each car and track costing money?? I have no idea how it works and am just looking for help.