Sweetcorn starts losing it's sweetness as soon as it's picked. It's best to blanch and freeze the cobs as soon as you can after picking.
Although I live in Georgia now, I grew up in the US state of Indiana, which is truly "corn country". I always heard that if you grew corn at home, the best you could ever taste is to start the water boiling before going into the garden to pick it. I only did it that way once . . . the old saying was right! Don't over-cook it, a few minutes is all you need. If you have and outdoor grill, you can wrap in foil and cook on the grill, or fold the green husks back from the corn, remove the silk, dampen the husks with water and fold back around the ear before placing on the grill. Cooked in husk is my favorite!
Pick it when the milk stage test shows that it is ready, don't leave it on the plant too long. Enjoy what you can while it is fresh, indulge yourself! But if you are going to preserve it on the cob, yes, blanch it and prepare to freeze it. You can also cut from the cob and freeze that. Or home can it.