Was doing it off the top of my head; was off on the exact number but the sentiment holds. The main benefit of the UK has been that it was an English-speaking intermediary for US companies. The Netherlands and Germany are filling that role as basically every white collar worker speaks fluent English.
The main power lever the UK has at this point on the global stage is the fact that its banks orchestrate and facilitate global money laundering at the intersection of corporations, organized crime and autocratic regimes. And is rapidly losing that role to crypto.
My reply is less harsh/dismissive than @hash9. Your last paragraph is powerful. I do think sometimes that I seriously underestimate the financial advantage that UK gains by having "selectively weak financial regulation" (my term). They are a like a Big Singapore, that pretends to be very well regulated, but looks the other way when autocrats want to buy 20M pound flats in Central London.
I expect they will try to extend their advantage in the coming years by using "selective legislation" to encourage multinational corporations to re-home to the UK. See: Unilever and Shell. This is only the beginning in my view.
I wouldn’t count on this working out long term. If this becomes the main advantage the UK has, it just becomes a consolidated target for anti-corruption initiatives. A country like that is also not a good one to live in, so they should expect to lose Scotland, NI and Wales to the EU. You only need London to launder money.