Welcome!
Unlike so many people, you have the good fortune to have a surgeon who discussed your different options and the pros and cons of each with you. We see so many people who, a few years post-op and not getting the results they expected from sleeve or gastric bypass, only then find out that there was something called a DS, and that the DS has the best statistics of any bariatric surgery for percentage excess weight loss, for maintaining that weight loss, and for permanent resolution of almost all comorbidities. I can't emphasize enough the importance of maintenance. Many people do well initially with sleeve or bypass, only to find themselves struggling to maintain their weight loss, even though they continue to follow their post-op dietary instructions.
there are excellent long term studies, with large numbers of patients, regarding the nutritional aspects of the DS. Yes, you do need to make a life time commitment to taking a fair number of vitamins and minerals, and to emphasizing protein in your diet. Yes, you will need regular lab work to check levels, at least annually (I do annually, other people do more frequently). But if you make that commitment and stick to it, the chances of nutritional deficiency is very low. Most of the people (NOT ALL!) who get into nutritional trouble do so due to noncompliance. In other words, it's up to you.
It's your decision. Keep in mind, though, that we see new people all the with with sleeve, lap band, or even gastric bypass who went into their surgery with high hopes and either never lost sufficient weight, or who lost and regained a large amount of weight, and now want revision to the DS. Even setting aside all the financial aspects, and how difficult or impossible it can be to get insurance coverage for a revision, it's a miserable experience for these folks to experience this failure, which their doctors and society will blame on them even though really it was the operation that failed.