Should I reduce cash back from credit card rewards from COGS?

Total Sold amount: $350k

COGS is $347k

Profit: $3k before expenses (supplies, mileage, credit card annual fee, etc)

CC rewards profits: $18.5k

If I reduce COGS by $18.5k, I owe $2k+ in taxes due to SE tax, but if I do not include the $18.5k, then I get a refund.

At this scale, do I even put it? ChatGPT says not to.