Supply chain issues

The property must be placed in service in order to deduct the expense.

See https://www.irs.gov/newsroom/irs-issues-guidance-on-section-179-expenses-and-section-168g-depreciation-under-tax-cuts-and-jobs-act

Equipment used in the production of income is not claimed until the tax year it is placed in service. It does not matter what tax year it was purchased or paid for either.

So, to be sure I understand, if my laptop gets delivered in December of 2021, but I don’t start using it in my business until January 2022, then I will claim the expense for tax year 2022. However, if I start using it in my business before the end of December, then I will be claiming it in tax year 2021?

You are correct.