Want to disable Keychain on iMac

Never do this period - You will destroy your OS.

It contains software licence codes , and certificates necessary for a host of things including your internet access.

It is vital .

Its rather more than simple password storage .

Whilst it’s not exactly the same as the windows register it does share some similar characteristics.

Mess with it at your peril .

Leave Keychain alone! It´s part of macOS and can´t be deleted. While stupidly tinkering with it a couple of years ago I completely toasted the OS on my iMac, and I had to wipe the internal drive and re-install the System and everything else from scratch! Fortunately I had up-to-date Time Machine backups and a clone. To this day I don't even open it because I obviously don't understand it properly. My advice: just forget about it! It´s a tiny app (4,9 MB) and can easily be ignored and left alone. You have been warned!! Regards, Ian.

I strongly recommend not doing this however it seems like it may be possible.

https://www.computerworld.com/article/3254183/how-to-use-icloud-keychain-the-guide.html