On the PC I would suggest Codemasters stuff. F1 2019 is one of the best offline racing sims around, huge number of tracks also selection of modern and classic F1 (and F2) cars. Has the best AI of any sim, which will race you properly and make mistakes etc. Ers on the game side of realism and has a host of difficulty options. Downside depends on how much you like F1 and its eccentricities. There is also Grid which provides non-open-wheeled racing, although not actually played that myself so can’t speak to its quality.
If you want to look off of PC then GT Sport on the PS4 is fantastic and really friendly for less experienced players. Has a good selection of cars of all types plus tracks from around the world, some real and some fictional. Again, focuses more on the game side of things rather than the sim, plus has a bunch of fantastic features like the driving challenges which really help you to learn cars and tracks. Also the online mode has a driving license system which is intended to reduce the number of wee bams you encounter.
If you want to go really sim-y then Assetto Corsa is the friendliest sim, it’s realistic but the handling gives you confidence and you can really chuck cars around. Has a good car/track mix and good online, although the offline stuff such as championships and AI is very lacking.