Such an interesting question. I think it depends on why you’ve started a new role in a new setting.
If it’s because you felt you had no other option but to leave then feelings of anxiety to not fall into another difficult situation can make you overcompensate everything to get things right and to feel included. That’s emotionally exhausting which could make the settling in process to be drawn out even though you’re grateful to be there.
If it’s because it was time – left on a high to better things, going from a positive place will accelerate settling in
If it’s because of a change in circumstances – having to move home etc, then homesickness could slow the process. The grass will look greener on the other side
Whatever the reason – the culture in the new setting will impact hugely. If it’s a culture of healthy belonging – you’ll soon settle in because you feel accepted and valued. If its culture of unhealthy belonging where you have to adapt yourself to fit in then I don’t think you’ll ever settle fully