NASCAT Heat is not a sim. You can say that it's a mini simcade or arcade, but it's definitely not a sim.
It's all about what style you want to play. NASCAR Heat let you drive on 4 series: Monster Energy, xFinity, Truck series and the Xtreme Dirt Tour. It's the usual career mode that you can expect: you can race for other teams or create your own team.
GRID it's that classic "arcade racing game that is not racing on a city". Seriously. How many arcade games you know that you can drive on circuits? There isn't one! You either have full sims (P. Cars, Assetto Corsa, DiRT Rally...) or simcades (GT, Forza, F1...). The only "true" arcade racing out there are NFS or Driveclub (excluding the other types of acade like TrackMania, Burnout or Horizon Chase).
GRID seems to be the choice. But, i have to say... i really don't care about Codemasters games anymore. DiRT Rally 2 had a mess of release, which famous rally cars were part of DLC instead of being in the base game, even though they were already available in DR1. F1 2019 is weird and they put microtransactions on it (seriously, microtransactions in a F1 game? wtf...). Only gods knows what the hell they are going to do with GRID...
