Safe storage for multiple passwords for multiple accounts

I copied the question from ‘Power user’ for a better visibility, hope it is allowed.

So, I’ve had this difficulty for a while, and I hope to get some feedback or referral to the sites where this problem may be discussed.

Nowadays all of us have multiple accounts, both personal and work-related (logins to web-sites or applications at work, logins to personal computers and mobile devices, etc.). I personally have more than 50 different accounts. In addition, some of those resources require changing password every month or so, and some of them require that the next password does not have the same combination of symbols as the previous one and that it has both capital letters and numbers and other symbols, well, you know…

How do you come up with so many different passwords that have different combinations of symbols and how do you remember all of them?

I feel that it is incorrect to record work-related passwords on personal mobile devices or in cloud storage. It is also prohibited by company policies. I also prefer not to record the passwords to the sites where I can manage personal finances or taxes.

Next, some passwords may be restored using the email that was used for registration. Some passwords may be restored using the phone number that was used for registration. How do you manage that? Do you record or memorize the correspondence between the emails and the sites/resources, and also logins? Do you use separate emails for money-related issues?

Are there any interesting articles on the topic? What is the correct way of working with this much complexity/is there a know how? Was there an idea that the creators of this system had in mind? How all this can be secure if we end up recording all these passwords?