Filipe, for the purposes of my argument, let's just pretend that I've never heard of this project before.
Making games is very hard. The business of games is also very hard. What you carry now is a big burden upon your shoulders, but I don't think you yet appreciate exactly how big your responsibilities are.
Firstly; you've never made or released games before this one. That's not a bad thing at all, and it's important that you start somewhere. The problem here, however, is that you're falling into very junior-level mistakes and you're unable to see these problems clearly. What I think you need to do first-and-foremost is step back, assess your strengths and weaknesses, and have a really deep think about what you want to actually do and more importantly, how it's going to be achieved.
As an example; open-worlds are not easy. Yes, you can go into Unity or Unreal, slap down a 4096x4096 terrain tile and throw some hills and trees at it, but that does not make your world interesting, nor would it work very well on even modern computers. Open World games are a massive challenge for professional AAA development studios, and they can have upto 300+ people working on a game at one time. You're one man at this stage. You need to keep this in mind, and make a decision on how much the Open World is worth, because I can promise that making an effective, fun, stable and optimised Open World is going to cost you financially, time-wise, physically and mentally.
One thing that really bothers me is the lack of a concise, clear and exciting pitch. What you've done is what every other newbie does on game forums; they try to give people just an idea, but they don't give you any information to prove that they can actually take the project the entire way through. You've not demonstrated us any time-management skills, you didn't upload images to show that you've actually tested the idea to check that it's worth pursing...for many people, this is a turn-off, as it gives the air of you maybe not being as committed to the idea as you actually are. People want the feeling of security; they're going to be dedicating time and effort to you which they could have spent working on paid projects; you damn well need to have a good pitch to show them why your project is going to be worth it.
Just on that; I also get the feeling you don't have a strong and strict game design document yet. You're using a lot of generalisations, which can show potential helpers that you're very..."floaty" in terms of changing your mind a lot. Going back to the security thing I mentioned before; Lead Designers who don't have a solid idea of what game they want to make tend to scrap their entire projects a lot and start from scratch, much to the annoyance of the rest of the team. I would recommend that you spend some time with Google Sheets or whatever and, even if it's just dot points, list exactly what you want, right down to the number of races, the race modes, all the rules, all the cars and their customisation parts etc. Know how big the job is going to be.
Overall, I feel like this project is not being based off of solid, tried-and-tested gameplay design concepts, but rather on your own personal ideas of what is fun. Too many bad games are developed for personal reasons, and I get the feeling you don't actually know who your audience is yet. I think you need to head to the drawing board and really carefully carve out a much clearer image of what you want and show us proof that it's going to be fun before you ask for help.
