I have a Mac mini and installed Turbo Tax 2024 Deluxe on it. When I try to install a State, I am prompted for "Keychain Access". Nothing I try does anything.

This is a MAC security feature. 

Follow the instructions below to get through the Keychain access

Mac not using Keychain

If you haven't given TurboTax Keychain access, you can select Forgot Password in the password request pop-up to answer your security question. That'll get you back in. Once you're back in, you can select Password Encrypt from the File menu if you want to update or remove your password altogether.

Mac using Keychain

In some rare cases if you've given Keychain access to TurboTax, you can go to Applications > Other > Keychain access > Keychains > Login > Category > Passwords > find Intuit or TurboTax and right-click Get Info > Attributes > Show Password.

You will be prompted for your Mac password and it'll show you the password you used to encrypt your TurboTax file. This is may not work for all users.

Disclaimer

Password protection of TurboTax CD/Download files is set by the user. TurboTax can't assist in unlocking the file or removing the encryption. If these steps don't help, you'll need to start over in a new file.

I have exactly the same issue.  It says it wants to use the information about "tmx-pbxl_uuid_service" but the PasswordManager which is the Mac replacement for the old keychain manager has no information on this.  I've tried all the passwords I have for Intuit, and none of them work.  Without being able to download the state, I'll not be able to file using Turbo tax.  And I don't seem to be able to get their attention that they have a major problem.

Did you try everything above?  If so, then please call customer service at 1 (800) 446-8848.  

Actually, my Mac login is what is expected. That worked for me.