I think properties of tracks shouldn't be comprised because there are lot of tracks like Spa-francochmaps, Mexico, Spain, Bahrain, Turkey, Singapore tracks are where tire wear So the best strategy should be undercut but because the tires wear out more due to distance, heat and higher number of turns. So the new tires on higher fuel load should be at least 0.5-0.8 faster on their out lap on the other car but it will not happen due to fuel. So other tracks where you can't get temperature in to tires like Monaco, Austria, Italy, Brazil it's good to go overcut. So I think there is not sweet spot for the any tracks in this game. If you don't have a sweet spot you can't imagine to have good strategies other than others are trying run longer and longer which makes no sense because you need to have more sweet spot and a balance between the tires and fuel load in the car.
You realise it’s a game right?
There should be elements of unrealism, so just play and enjoy.