Thanks for the list of password managers. I haven't tried any of these until today as I have been using the same set of 2-3 passwords on multiple sites.
But seems like the open source password managers from the above list can be a good try.
With the number of sites we use on daily basis, such password managers will be helpful to store our passwords.
Using same passwords on different sites is very bad practice. If you use a same email address, a same password on multiple sites, if it is leaked, compromised on only one site, you will possibly lose access to your accounts on other sites too.
You can use
https://haveibeenpwned.com/ to check whether your email addresses are in data breaches.
A complex password with a combination of uppercase, lowercase, numbers and other symbols is a good alternative to be used in protecting something that is considered necessary.
Theoritically it is like this, but if you set up your passwords manually, you will have probability to create similar patterned passwords, and in password security this is not a good practice.
With password manager softwares, your passwords will be created randomly, no patterns from your previous passwords.