Youtube - how to transfer settings to another account?

Question

YouTube

I had a youtube account linked to Yandex mail. One day Google tells me - link your account to gmail, you are not in danger. OK.
Tied, youtube asked me - what do you want to use? Yandex - I answered. OK. Use it. For the past month, every time I went to youtube, I was transferred to a gmail account. I switched to Yandex and OK with two mouse clicks. But today the Yandex account is gone!!!
All subscriptions, all comments and personal videos from Yandex are gone. Why did they disappear? Because I can't log into my youtube account under Yandex mail. Allows you to log in only under gmail.
Question.
1. How can I log in with my old account to copy at least my personal playlists?
2. How can I transfer all my settings from my old account to my new one?
3. Whom to sell the soul to return everything as it was?)