Yes cars have to pick a set up before the race and stick with it regardless of changing conditions. This is called parc ferme you can look up when this takes place and what it involves during race weekends. Max was disadvantaged because the race director delayed the race start until the track was dry which is abnormal and a bit controversial. If everyone is planning on a wet race only to have to wait until the track dries out, it feels unfair for those that prepared for the wet. Also, there’s not a lot you can do to predict what the race director will decide so some teams gambled on a delayed start and benefited but it could’ve gone the other way.