How does matchmaking work in MTG Arena?
Nobody really has any hard evidence for how the matchmaking algorithms work, but I've always been matching with people my rank when it comes to ranked play. It could be that there are less new people than there used to be, so it might start matching you with someone "close enough" if it takes a while, like many other multiplayer games do.
When it comes to unranked play, I think the game still matches you with people around your level. What you felt could've just been you leveling up and slowly starting to play with people that understand the game, but it's still hard to tell if easy wins are intentional or not because unranked play is usually full of people that are just trying new decks and losing quickly.