If you’ve got the best lens in the world – whatever that means – and you make a weak picture, you’ve got a weak picture.
If you’ve got the worst lens in the world – whatever that means – and you make a strong picture, you’ve got a strong picture.
The point of the matter is that your equipment, including your lens, is less important than your ability to make strong pictures.
Your ability to make a strong picture is related to your excellence in craft, not to the excellence of your equipment.
If you’re more concerned with the excellence of your craft rather than the excellence of your equipment you’ll be the best photographer that you can be. Not to mention the cash you’ll save.