In general, and if there is a tax treaty with your home country:
Most tax treaties say that your social retirement benefit (equivalent to US social security) should be taxed in your home country according to your home country's rules, and only your other income is taxed in the US. This is the strategy of "relying on the treaty" as we might say.
Or, you can ignore the treaty, not pay tax in your home country. In this case, the income is fully taxable in the US because, as a US resident, all your world-wide income is usually taxable in the US.
However, to know which exact rules apply to you, we need to know the country, among other details. @pk is the absolute expert on this forum for this topic area.
If you paid tax in the US on all your foreign retirement income, instead of only on the portion that was not taxed in the foreign country, that is your mistake in preparing your returns. There is a way to declare your foreign income as not taxable in the US due to the treaty. The typical remedy would be to file amended US tax returns to adjust the amount of taxable income you report, so you are only taxed on the correct portion. If the amended return results in lower tax, the difference would be refunded back to you. You can amend your 2022, 2023 and 2024 tax returns. It it too late to file an amended return for refund for tax years 2021 and earlier.
If you just want proof of what you reported to the IRS, so you can show that to your home country (that you paid tax on all your retirement, for example) you can get transcripts of your returns going back 10 years.
https://www.irs.gov/individuals/get-transcript
