Its the most easy way for me and I don't want to deal with a third party tool for every day use. I use a third party password manager, but it is annoying in daily usage for me. I use it to store all passwords, so it has its use.

FYI, Firefox still has a profile manager, good for separating work and personal life. That makes the password manager very portable as you can sign into different Mozilla accounts in each one, to keep distinct sets of sync data. It's easy to create a separate shortcut/launcher file that starts up a secondary profile by adding these arguments to the command:

-P yourprofilename

However, I gave up on the inbuilt password manager. It's too simple, you can't edit entry labels, edit URLs (e.g. when site's main domain changes), or store anything other than usernames and passwords (e.g. notes).