Pick up the not frozen discard pile having a Canasta meld
Yes you can; this is one of the main differences between the discard pile being frozen or not.
Source:

When the discard pile is not frozen against their side, a player may take it: a) with a natural pair matching the top card as above; or b) by melding the top card with one matching natural card and one wild card from his hand; or c) by adding the top card to a meld they already have on the table.

Source 2:

But first let us consider the case where the discard pile is not frozen against you. In that case, if the top card of the pile is a natural card (from four up to ace), you can take the pile if either:

you play two cards from your hand that make a valid meld with the top discard: these could be either two natural cards of the same rank as the top discard, or one such natural card and one wild card,

or

the top discard matches the rank of one of your partnerships existing melds, and you add it to that meld.


If the pile is frozen; then you must have 2 naturals in hand.