There is limited official documentation on the matchmaking process. But I believe that in the Apprenticeship ranks, the algorithm looks at a combination of rank and MMR (a hidden internal rating based on earlier match results, a bit like the ATP score in professional tennis).
So you should be competing against opponents who are also in the higher part of the apprenticeship ranks, and who have similar average match results as you. That last part, similar match result, should not be translated at “same deck quality”, nor as “same play skill”; it is a combination of the two. They may be starting players who spent a lot of money to instantly have the “best meta” decks, but no clue how to play them well. They may be players with decks that are totally terrible, but who navigate them like a pro. Or they may be players who, like you, make the best decks they can with their collection and their game experience and play them as good as they can.
My advice to you is to ask yourself: where is YOUR fun in playing this game (and note that this is a question with no right or wrong answer, it’s personal). Do you enjoy crafting decks with a limited collection and trying to squeeze the occasional win-against-the-odds? Do you enjoy a fast climb of the ranks? Do you enjoy learning to play one deck, or a few decks, well, and getting satisfaction from your own realization that you are improving, even when you still lose matches? Is your fun in trying to collect as many cards as you can without spending money? Or do you enjoy something else completely?
How to proceed with the game (and whether to proceed with it at all) depends highly on what makes the game fun for you.
