So let me do a broader overview.
If you leave the employer, you normally have 60 days to repay the loan in full. Any unpaid amount is called an "offset distribution" and is reported as taxable income to you on a 1099-R, that will likely be mailed to you by the plan administrator by January 31.
You can simply take the event as a distribution and report the taxable income. You will pay regular income tax on the amount of the distribution. If you are under age 55, you will be subject to a 10% penalty. If you lost your job due to the pandemic, you don't pay the 10% penalty, and you have the option of spreading the income over 3 years instead of 1 year. (Be aware, this part of Turbotax won't be ready until mid-February at least due to IRS delays.)
If you want to pay off the loan and reinvest the money, the plan might offer an extension beyond 60 days. If not, you can invest the money in a private IRA or in the 401(k) of your new job by calling it a rollover. Any amount you put into a new plan as a rollover is not counted as taxable income--it's as if you withdrew it from the old account and rolled it over into the new account. You have until April 15 to roll over as much as possible, or October 15 if you apply for the extension to file your tax return. On your tax return, you would report the 1099-R as a taxable distribution, and then when asked "what did you do with the money" you would report that you rolled over part or all of the money into a new qualified plan. Be sure that if you do make rollover contributions to a new plan (your new 401(k) or an IRA) that you tell the plan administrator this is a rollover before you make the contribution. There may be a special form. If you don't tell them ahead of time, it may be treated as a regular contribution instead of a rollover.
