Assuming true T2DM and no misdiagnosis, it's impossible to call without first knowing whether you are still overproducing or have progressed to underproducing. If it's the former then it's highly probable that no amount of insulin in the world will improve your long term heath outcomes beyond a superficial and temporary drop in blood glucose. Unfortunately your doctor almost certainly doesn't know this and will disagree if challenged, so proceed with caution and never assume medical professionals know what they're talking about just because they wear a white coat or blue dress.
If you're underproducing then the picture is way more complex and it's likely that some exogenous dosing may help, but you'll still be type 2 and will still be insulin resistant, so the goal should always be to cut the diabetes out at the roots with dietary change.
EDIT: If you do end up using insulin, make sure you become a pro user and know the potentially fatal dangers of overdosing before later marching headlong into any dietary changes.