There haven’t been many royal divorces recently, but what happened to Princess Tessy of Luxembourg was instructive. She was married to a younger son of the reigning monarch (Grand Duke is his actual title) and had two young sons when they divorced in the UK courts - which are generally seen as favouring fairly equable awards to divorcing spouses.
Anyway, despite her in-laws being worth more than four billion (they are one of the very wealthiest royal families around) Tessy got to stay in the marital home, and received an allowance of £4000 per year per child. The court was very clear that the family’s wealth was not shared with the younger son, and although he was paid an allowance by his father, his wife had no claim on as it was not his money. She only had a claim on his individual assets, which you can see from the settlement, were modest.
Harry has more individual assets. But he’s not currently paid an allowance (so far as we know) so it’s unlikely any court would make an award that went further than Harry’s own assets. And if there were a divorce (obviously, this is hypothetical), it would entirely depend on where they chose to get divorced as to how they’d work out which of Harry’s assets would be considered marital property, and so in the pot to be divided.