Is personal allowance used up by being paid in America?

I have just started a limited company in the uk and I’ve been contracting my services since jan 1st 2021. Previously I was being paid by an American company. All tax etc. was done in America and I was paid in dollar. My question is: now that I’m back in the UK and will be payed by a British company (my own company that is) do I still not pay income tax on the first £12500 I earn until 1st April? Hence, the best way to pay myself would be to use up my personal allowance until April and only pay NI and then in April start a new dividend / salary split?