This may help.
Why can't I link my 1099-NEC in TurboTax Online?
When the 1099-NEC is entered on its own before creating a Schedule C, the program is having issues. If the Schedule C is done first and the 1099-NEC is entered within the Schedule C, then all is good because TT does not have to 'link' it to a Schedule C. However, there are a multitude of other issues in TT related to 1099-NEC that this won't fix -- such as when there are two taxpayers with 1099-NEC. Ownership of the forms is not being retained correctly.
Additional LINK
