A single member LLC is considered a disreguarded entity by the IRS. Under no circumstances and with no exceptions does the owner of a single member LLC issue themselves a W-2, 1099, or any other type of tax reporting document.
If you filed form 2552 to have your single member LLC "treated like an S-Corp" for tax purposes, then from the income tax point of view, you don't have an LLC. You have an S-Corp. The rules are completely different for an S-Corp. None of the below applies to an S-Corp.
If your single member LLC was open for business in 2020, then you are required to report it on SCH C as a part of your personal 1040 tax return. Doesn't matter if you had no income.
Any expenses incurred before your single member LLC was "officially" Open for business are claimed as start up expenses in the first year the business is officially open for business. It does not matter in what tax year those startup expenses were incurred either. THe program will ask you for any startup expenses.
