I get the following message on my phone: "confirm if it's you recovering your account" But I didn't do any recovery and of course I didn't press any button.
It happened already two times.
What does it mean? Does somebody is trying to hack my google account?
I have 2 factor google authentification, but didn't get any SMS, which is supposed happens if somebody is trying to change my password.
I found the following discussions on:
google community
reddit
but it isn't clear for me what does it mean and what should I do.
If you were actually trying to recover your account, you should have received such a message.

You didn't, and it looks like a glitch as the Google help you linked suggests.

One option is do nothing, a better option would be review your account, sign out of unused devices, and change the Google password to a strong one. This question from our sister site is useful XKCD #936: Short complex password, or long dictionary passphrase?. Generate new 2FA codes, keep them securely.

Obviously, the second option is better because, you did a security check and changed passwords / 2 FA codes. As an added precaution, be on the lookout for Google security mails in your inbox.