Everyone has different skin sensitivity, hair thickness etc so I think you need to experiment a little to find the formula which works best.
Blades can change the feel of a razor. There are lots to choose from. These cover the range from mild to sharp, in order: Derby Extra, Astra Superior Platinum, Astra Superior Stainless, Gillette Nacet.
If you like stainless steel razors take a look at Karve. They make a wide range of plates from mild to aggressive. That makes it easier to experiment to find the one which suits you best.
Skin stretching might help a little with neck irritation. Throw your head back and to the side. Maybe pull down with your free hand. Light touch. If the blade seems to tug at all definitely try something sharper.