Export passwords from outdated Keychain Access on Mac Monterey (not Passwords app)

Howdy folks,

I'm running a 2015 macbook stuck way back in Monterey 12.7.6, plus a 2020 iPhone 12 running 18.5. I need to upgrade my mac, but in the meantime, my Keychain Access has become a hot mess.

My macbook runs Keychain Access (please note this is NOT Apple Passwords, which is not supported on my 10 year old computer) which has a variety of passwords strewn across several distinct keychains - 2 default (login & icloud), 1 custom (updated login) and 2 system keychains (system & system roots).

When my phone updated to 18, it got the new Passwords app, which i guess saves to icloud, but a different part of icloud that doesn't sync with the icloud keychain on my mac.

I'm tired of the whole shebang and would like to consolidate all this data into one file, keep only the latest version, and upload it into proton pass, using that as my password app from now on.

I can pull a csv from the iphone Passwords app, but Keychain Access on Monterey will not let me export password data. (here's confirmation: You can export some keychain items (for example, certificates and keys) from one computer and then import them into Keychain Access on another.

Note: You can’t export passwords from Keychain Access.)

Copying and pasting 1400 passwords one by one is out of the question, and I'm out of ideas. Google fu was no help.

Maybe I can screenshot each page of keychain access and crop each column so I can copy and paste sections into a spreadsheet, but hoping there's a better way, especially since the phone's csv export doesn't include dat/time so figuring out the most recent password for each log in will be a challenge.

Hope that makes sense, TIA!