Can I claim the real estate taxes I have been paying on 2 houses that I inherited but they were not in my name until 4/2024. I paid the taxes in 21, 22, 23 and 24

You can only deduct real estate tax on property that you own. The tax must be "imposed on you." You should consult a lawyer to determine when you became the legal owner of the houses or the owner of record.

For any real estate that you can deduct, you can only deduct it on your tax return for the year that you paid it. If you were legally allowed to deduct real estate tax in a past year, but you did not deduct it, you would have to file an amended return for that year to claim the deduction.

You might not be able to deduct real estate tax that was delinquent when you paid it. Again, consult a lawyer.

Real estate tax is an itemized deduction. It will not reduce your tax or increase your refund unless your total itemized deductions are more than your standard deduction. Furthermore, for 2018 through 2025, the total deduction for state and local taxes is limited to a maximum of $10,000 per year ($5,000 if married filing separately). The maximum applies to the total of real estate tax, personal property tax, and either state and local income tax or state and local sales tax. So if you already deducted the maximum amount, adding more real estate tax will not make any difference.