VK was hacked, Telegram was hacked a week later, how could this happen?

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Hello.
Last week my VKontakte was hacked. Access was restored, the password was changed. This morning, the megaphone signed up for a paid mailing list of some videos, I unsubscribed. Now my wife wrote, a scammer from my Telegram account extorted 2k rubles from her. I was unable to restore access to my account and did a hard reset. I wrote to friends, like my old account became deleted. Three questions -
1 - How can you hack a cart when there is no access to the phone?
2 - Does the fact that I reset my account mean that the scammers have lost access to it? They will not be able to do things to me from there for life (if they have not done it already)?
3 - How to protect yourself in general? I have Windows, Avast antivirus is free. Could it be some sort of system leak? Some kind of keylogger, although I haven’t logged into telegrams for a long time to write a password. How do advanced users generally manage and keep accounts secure? I'm ready to switch to some kind of paid protection, but I don't know what.
Please reply, thank you in advance.