Silencing WhatsApp chats and groups for 1 year is not enough? The development team is working to introduce a change that replaces this option with an indefinite stop. The option to disable notifications for "Always" was spotted in the beta version 18.104.22.168 of the WhatsApp app for Android, is currently under development and cannot be tried yet. The screenshot shared by Wabetainfo allows you to take a look at the renewed menu to silence the notifications in which the new option stands out:
The options for now available in the stable version of WhatsApp allow you to stop receiving chat and group notifications for 8 hours, 1 week or 1 year. The latter choice should already be sufficient for most users, but evidently WhatsApp wants to satisfy even those who do not want to take the risk of forgetting to renew the option after 12 months. Muting notifications for a more or less prolonged period is the solution chosen by those who do not want to completely abandon a group, but at the same time do not want to be bombarded by messages from groups or overly talkative users.
It is not yet known when WhatsApp will decide to make the new option available for everyone, in the meantime you can fool the wait with the latest news introduced in the stable version of WhatsApp for Android that include animated stickers and QR codes.