I'm only looking into VR now, but as for racing sims.
Project Cars 2 is great for visual and breadth of content. The thing that lets it down is that it tries to bite off some seriously complicated stuff like proper tyre simulation, then gets itself all tied up in bugs. The concept tyre modelling in PCars2 is amazing, but the implementation is frustratingly different. Even if it did work without bugs, the AI don't use the same model, so any tactics and strategy you might want to play out based on tyre wear, weather and pit stops is immediately mooted as the AI will be uneffected while you are. Out side the the tyre model the same applies to the rest of PCars2. Great concept, poor implementation, full of bugs. You will find some classes or car at some circuits completely undrivable. Cars which can't be driven except on wet tyres for example. The net code is full of holes with random disconnects and lobby splits etc. This is what is primarily holding PCars2 back from being taken up by commercial eSport.
Race Room Experience which I installed at the weekend after dozens of recommendation seems much more focused on the racing rather than the features list and graphic detail. This makes it ideal for online championships and eSports. It's almost proud of the list of things it doesn't support. It's free to play with default content, you pay for tracks and cars. It has actual money winning eSport events and many more community events to enter.
So to answer your question with recommendations.
Start with Raceroom as it's free.
Consider PCars2 and Assetto
F12018 is worth considering, though most simcade.