How do I avoid double counting 1099-Misc income when it was already included as income in Quickbooks Self Employed and transferred to turbo tax?

It is your choice how to report Form 1099-MISC income, assuming that it was included in your accounting already.

Option 1: Enter Form 1099-MISC separately and back out the income from QuickBooks Self-Employed that was duplicated on Form 1099-MISC.

Option 2: Since the records are coming directly from QuickBooks Self-Employed, it is acceptable to keep Form 1099-MISC for your records and not adjust the income from QuickBooks if it was included in that accounting.

However, depending on how this income was received, there may be a larger issue. The Form 1099-MISC may need to be reported on Form 1099-NEC. In such an event, the issuer should send a corrected Form 1099-MISC and a Form 1099-NEC with the income.

From IRS Instructions for Forms 1099-MISC and 1099-NEC (2020)

Specific Instructions for Form 1099-NEC (For a brief overview, see What is Form 1099-NEC?)

File Form 1099-NEC, Nonemployee Compensation (NEC), for each person in the course of your business to whom you have paid the following during the year:

• At least $600 in:

1. Services performed by someone who is not your employee (including parts and materials) (box 1);
2. Cash payments for fish (or other aquatic life) you purchase from anyone engaged in the trade or business of catching fish (box 1); or
3. Payments to an attorney (box 1). (See Payments to attorneys, later.)
    

Specific Instructions for Form 1099-MISC

File Form 1099-MISC, Miscellaneous Income, for each person in the course of your business to whom you have paid the following during the year:

• At least $10 in royalties (see the instructions for box 2) or broker payments in lieu of dividends or tax-exempt interest (see the instructions for box 8).
• At least $600 in:
  1. Rents (box 1);
  2. Prizes and awards (box 3);
  3. Other income payments (box 3);
  4. Generally, the cash paid from a notional principal contract to an individual, partnership, or estate (box 3);
  5. Any fishing boat proceeds (box 5);
  6. Medical and health care payments (box 6);
  7. Crop insurance proceeds (box 9);
  8. Payments to an attorney (box 10) (see Payments to attorneys, later);
  9. Section 409A deferrals (box 12); or
  10. Nonqualified deferred compensation (box 14).