Unpopular opinion.
Putting all the conspiracy theorists aside the intent of the law is actually to gain what western countries have a new phone that has localized apps that non-English speakers can use.
For some apps, like twitter, translation of the ui is enough for some others local apps are just better.
Knowing how laws are being implemented in Russia it is hard to tell what this will turn out into, most operators already wrote an open letter to the president to not sign the law, but it was still signed.
So I see it more as an attempt to created isolated marked similar to china one rather than total surveillance scenario.