Setting up Thunderbird and instant incoming mail notifications?

Question

Mozilla

I have a mailbox on Yandex.mail. I want to set up Thunderbird on two machines so that if I mark an email as read on one, it will show up on the other at the same time.
Similarly, about incoming letters: I want them to instantly appear in the Inbox of both computers. Ideally, the same instant synchronization of Sent.
As far as I understand from the documentation, IDLE is responsible for this (sometimes they are mistakenly called push email and push imap) and everything should work by itself. I have set up IMAP on two machines, but mail arrives with delays and not at the same time. Please let me know what needs to be configured to make it work.
I'm specifically interested in this feature: kb.mozillazine.org/IMAP#Push_support

Answer 1

It does not "come" and the mail client is synchronized. The default is once every 5 minutes. You can try to reduce the time in the mailbox settings, but I won’t say how Yandex will look at it (especially if from different IPs)

Answer 2

Account Properties - Server Settings - Advanced - Use the IDLE command if it is supported by the server
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