Don't confuse itemized deductions on schedule A with your business expenses/deductions on schedule C. They are separate. For Schedule A personal deductions, you get to take your itemized deductions or the standard deduction, whichever is larger. Itemized deductions are things like Medical, Gifts to Charity, State Income Taxes Paid, Mortgage Interest, Property Taxes, Car Registration fees, etc.
You get to take both, your business expenses AND the Standard Deduction (or your personal Itemized Deductions). And you have to enter your business expenses. Be aware, if you have self employment income you can get in trouble for not reporting all your expenses to qualify for the EIC.
So yes on a Joint return your Schedule C loss will be deducted from your total joint income. And you still get the Standard Deduction. For 2022 the Standard Deduction is 25,900 plus 1,400 for each spouse 65+.
