Pound Plunges to Record Low as Kwarteng Signals More Tax Cuts

I don't understand why investors are losing confidence in the pound. On the fiscal side, the government will need to borrow a bit more to offset the loss in tax revenue but fundamental productivity has not changed. Raising interest rates to curb inflation doesn't affect affect government debt since they print currency. Subsidizing energy costs helps consumer spending. Lower taxes is a boon for entrepreneurship and attracts FDI. Generally speaking governments in developed countries that reduce regulatory barriers face higher economic growth, in the short term at least. The Truss government is doing almost everything by the book in terms of economic stimulus, why is the market responding the opposite way?