I suggest buying the jalapeños and letting them sit a week to soften (and hotter!). They cook better and don’t have as much of crunch when cooked.
Can grill, do in the oven, or even better in the Air Fryer at 350 degrees for 10-12 minutes. For making a large batch to freeze — lay them on a tray with parchment paper then toss in the freezer. Once they are frozen, toss them all in a freezer bag and take what you need when you need it.