Just my opinion here
I suspect there are some serious methodological flaws in this study, I am not qualified to judge this, but if any readers with research experience are, feel free to comment.
It is worth noting that this is not published in a peer reviewed journal. "However, it’s important to note that they do an internal peer review, but no third party peer review"
There have been a lot of studies on weight regain after weight loss, as in hundreds to thousands of papers on the subject. The results of this study are not consistent with the previous research.
In general most studies over the past 40 to 50 years show that most people who lose weight regain all or most of that weight over the next few years. Irrespective of how they lost the weight. This has been my personal experience as well.
The SURMOUNT-4 Randomized Clinical Trial
After 36 weeks of open-label maximum tolerated dose of tirzepatide (10 or 15 mg), adults (n = 670) with obesity or overweight (without diabetes) experienced a mean weight reduction of 20.9%. From randomization (at week 36), those switched to placebo experienced a 14% weight regain and those continuing tirzepatide experienced an additional 5.5% weight reduction during the 52-week double-blind period.
This is a prospective, controlled, randomised clinical trial published in a reputable peer reviewed journal JAMA Journal of the American Medical Association
It showed 20.9% weight loss with tirzepatide, after ceasing it over a year, the ones on placebo gained 14%, leaving average weight loss of 6.9%, those who received tirzepatide lost a further 5.5%.
There are many other good quality peer reviewed papers that show similar results for tirzepatide, semaglutide and all other weight loss methods over decades excepting surgery.
Sorry but that study sounds great but is not likely to be accurate, there is very little description of their methods of getting and interpreting the data they used so it is not really possible to assess what went wrong. They are making extraordinary claims, that are different to the established body of research, do not acknowledge this in the article and fail to provide the extraordinary evidence to back up their claims.
One of the great things about access to inexpensive GLP-1 drugs is you can experiment with stopping and starting and increasing and decreasing doses as needed. Based on the research, I think most people are going to need to stay on the dose they used to lose the weight, to keep it off, but trying reduced doses or stopping it for maintenance is a easy harmless experiment so long as you don't let weight regain get away from you before restarting it if necessary.