Why does TT say to only include the RMD amount for this IRA account? It appears to not allow to take my full RMD for all accounts in only one IRA account. Is that right?

Yes, if you have multiple IRAs then you can take all of your IRA RMDs from only one IRA account. Please see Can an account owner just take a RMD from one account for additional information.

Please follow these steps in TurboTax Online:

1. Login to your TurboTax Account 
2. Click on "Search" on the top right and type “1099-R”
3. Click on “Jump to 1099-R” and enter your 1099-R
4. Continue until "How much of the $XXXXX was a RMD?" screen and select "Only part of this distribution was a RMD" and enter the amount of RMD /or select "The entire distribution was an RMD" (if this distribution includes RMD for other IRA accounts then you included the amount here)
5. Enter the RMD amount for this account on the "Let's get more information about your Required Minimum Distribution (RMD)" screen
6. On the "Review your 1099-R info" screen click "Continue"
7. On the "Did You Miss a Required Distribution From Any Retirement Accounts?" screen select "An IRA..."
8. On the "Total RMD for all other IRAs" screen enter the RMD from your other IRAs (where you didn't take a distribution from).

In TurboTax Desktop:

1. Click on "Search" on the top right and type “1099-R”
2. Click on “Jump to 1099-R” and enter your 1099-R
3. On the "Required Minimum Distribution" screen enter RMD for this account 
4. On the "How much of This Distribution Applied to your December 31, 2024 RMD" select "Some of this distribution…" and enter the RMD amount / or select "The entire distribution applied…"  (if this distribution includes RMD for other IRA accounts then you included the amount here)
5. On the "Your 1099-R Entries" screen click "Continue"
6. On the "Did You Miss a Required Distribution From Any Retirement Accounts?" screen select "An IRA..."
7. On the "Total RMD for all other IRAs" screen enter the RMD from your other IRAs (where you didn't take a distribution from).