What canonical should be set for a multilingual page?

Question

Search Engine Optimization

I have a page available in multiple languages ​​and expecting more to be added

1. example.com -- English (default)
   
2. example.com/ru/ -- Russian
   

What should be example.com/ru/ ? Should it point to itself or to the English version (the default version)? Also spelled out:link[rel="canonical"]

<link rel="alternate" href="https://example.com/" hreflang="en"/>
<link rel="alternate" href="https://example.com/" hreflang="x-default"/>
<link rel="alternate" href="https://example.com/ru/" hreflang="ru"/>

Answer 1

on yourself
if on EN - you will lose traffic from language

Answer 2

Why do they need a canonical at all?
Let them be independent