Q. Looking for a legitimate way to report this as earned income (and not self employment income or a scholarship).
A. It doesn't exist.
Academic stipends are typically reported as taxable scholarship*, depending on the setting (what does "national lab" mean).
Internship is normally wages and is subject to social security and medicare tax, either as W-2 withholding or self employment tax (and a 1099-NEC, rather than 1099-misc).
*Scholarships are a hybrid between earned and unearned income. It is earned income for purposes of the $15,750 filing requirement (2025) and the dependent standard deduction calculation (earned income + $450). It is not earned income for the kiddie tax and other purposes (e.g. EIC). For grad students and post grad fellows, scholarship, stipend and fellowship income is earned income ("compensation") for IRA contributions.
Taxable scholarship goes on line 8r of Schedule 1, from which TT treats it as hybrid income.
In TT, enter stipend/scholarship in the 1098-T interview as scholarships not shown on the 1098-T.
