what was reported on the 1099-INT and 1099-B sounds correct. 1099s are the official tax reporting and what you should follow.
I think the brokerage is wrong to say this AMD is a capital gain. Selling a note can generate AMD and a capital gain/loss, but holding to maturity should be all AMD. By "match the paper statements" do you mean trying to match how the brokerage is reporting it in monthly statements where they sometimes show YTD interest and gain/loss etc, which doesn't match their 1099 reporting. Some brokerages struggle with this stuff (and not kept up with elevated retail holdings in Treasuries since 2022), and these statements are not official tax reporting; e.g. Merrill can't even show T-Bill interest in their YTD interest on statements or online, even though 1099 is correct (those just hit 1099-INT Box 3, different to how T-Notes behave).
One other point on the 1099-INT when you bought the bond if you paid accrued coupon interest, be sure to adjust for this to reduce your income/tax. It should be applied in the year of the first coupon payment after purchase so if you bought the bond in 2023 but it didn't pay coupon til 2024 you would apply it in 2024 taxes. There is a question after you input the 1099-INT in EasyStep whether you need to adjust this entry and you should get a question for accrued interest. Finally, if you 1099-INT has a mixture of boxes (1,3,8) for different types of bonds and you have accrued coupon interest adjustment then TT won't know whether it's an adjustment for which box and will spread it over everything. In this case you need to split up the 1099 and input each of these separately (along with any corresponding premium from Boxes 11-13) to apply any accrued against the correct one(s).
Once the 1099s are in... you may have also noticed in these threads there is an issue with state reporting, if that matters for your state, you should see the $500 from 1099-INT is not taxed on your state taxes, but the $1000 AMD is. There is some debate on state exemption for AMD and it depends on the language in your state tax code. Assuming it's exempt in your state (can't advise on that), you should be able to enter a "miscellaneous" subtraction in the TT state program with an explanation statement, tho some people have commented this precludes e-file.
Personally I've stopped buying low coupon notes due to these issues, so if you are actively buying Treasuries I would try to stick to T-Bills for short maturities (< 1 year) and higher coupon notes (>4% depending on market) for longer maturities, ideally with a little premium (priced a little above 100) so you don't have any AMD on the 1099-B, or very close to par to minimize the state tax issue.
Caveat - Not a CPA/Expert but above is my understanding based on experience dealing with these issues.
