Does every russia & south america game and dlc get locked?

It would say "This package can only be run in specified countries" if it was locked for play. So if you plan to move or used vpn to activate you should be fine. Unless I missed something of course or something changes down the line.

AFAIK every game purchased from South American and Russian store is region locked and some and region locked to play (not only in activation)

For region locks you can see steamdb (a lot of games have no lock of any kind), but every GIFT you buy is region locked and can be activated in specific regions only.

Going by the title of the topic this might be useful: if you purchase from the Steam Store as a gift and from a restricted region (like South America or RUS+CIS) then that gift can only be redeemed by an account from that region. It warns you before you complete a purchase if that is the case. The gift can still be sent or traded however. Now if what you purchased is a key for the sub you linked to then it doesn't seem to have any restrictions regarding activation or play AFAIK.