How do I save specific cookies in Firefox version 64 and higher?

I believe Firefox version 64 was when they changed the cookie jar policy. Prior to this I was able to set firefox to delete cookies and browsing history on exit. It would retain cookies I wanted to keep such as my yahoo homepage so I wouldn't have to login every time. Now no matter what options I check it will not keep me signed in to Yahoo. Is this a Yahoo problem or a firefox problem? Supposedly they made some changes for better security but now I have to keep all cookies and delete them manually. This is a pain and in no way more secure since I have tons of cookies being stored on my computer if I forget to manually remove them. Firefox used to be good. Not so much anymore.