It’s not as simple as insulin -> more weight. It is calories in vs calories out but if you’re not adjusting yourself insulin intake based on your calories then you’ll have issues. Essentially as you reduce your calories and increase your excercise you should be taking less insulin. If you’re taking the same amount of insulin at a lower calorie (or carb) intake you’ll have increased hypos which will result in more calories obviously to treat the hypo.

Stop focusing so much as whether or not insulin makes your gain weight since it’s just one component. Increase your exercise and make slow adjustments to your diet. Be diligent with logging/tracking as much as you can, barring any other hormonal/medical component as you increase your exercise and reduce your calories your insulin need will lesson but this happens as you lose weight, it’s not necessarily one after the other.