What should I do? How do I get rid of him?

For a long time a person or several has been trying to get into accounts that i have and it does it because i use the same password for most of the accounts i have. So far this has already happened on steam, minecraft spotify, my second discord account, my email and another account where I spontaneously no longer know which it is. As mentioned above, he also tried it on spotify and as a result, in the email where I was informed of a new registration, I found out that the guy is in Russia. I have already changed so many passwords XD and my question now is how to get rid of it, except for all accounts I have to change the password (to different passwords, of course)

Not at all. Change passwords and is good.

Just have to change your passwords regularly and also use good ones, if he has to constantly look for it, it will be too annoying for him at some point.

Change heavy passwords and every 2-4 months, with important acc a little more often.

Change passwords and it's good. Secure mail accounts in particular. They are the most important.

When you've done that, rest.

He just noticed that the password works and is now trying it out everywhere. After enough failures, he will turn to another.