Your own link "Chest Reconstruction and Chest Dysphoria in Transmasculine Minors and Young Adults" says most people who got top surgery as teens do not regret it. "Self-reported regret was near 0."

But that paper was about a 10-minute-long survey of girls & young women who had double mastectomies relatively soon after their surgeries; it wasn't an in-depth study that followed up patients long term. Of the 68 trans-identified double mastectomy patients surveyed, 59 had their breasts removed less than two years before they were surveyed. Moreover, 28% of the clinic patients who had double mastectomies and were intended to be included in the study did not participate - 24 because they "could not be contacted" and two because they "refused the survey." That's a lot of patients left out.

Nearly half (49%) of the 68 patients surveyed had been under 18 at the time they had their breasts removed, and nearly half (48%) of the ones under 18 were 15 or under when they had their double mastectomies. It's unrealistic to think that teenage girls and young women who have been through this sort of surgical trauma, and caught up in gender identity ideology for years beforehand, will be in touch with all their feelings about the surgery 12-24 months afterwards, and it's even more unrealistic to think traumatized girls & young women will honestly and forthrightly reveal all their feelings when someone from the clinic that caused to the trauma happens to call them on the phone for a brief survey. At the same time, there's good reason to believe that the clinic workers who called the surgery patients might not have been open to hearing and recording the responses of girls & women who tried to regrets or mixed feelings.

Also, it's telling that the paper doesn't provide a copy of the 10-minute-long survey showing exactly what it involved. We just know that it consisted of statements that the participants were asked whether they agreed or disagreed with and how often. About surgical regret, the paper simply says

All postsurgical participants (68 of 68; 100%) affirmed the statement, “It was a good decision to undergo chest reconstruction.” Sixty-seven of 68 postsurgical respondents reported no regret about undergoing the procedure. Only 1 participant (who was older than 18 years at the time of surgery) reported experiencing regret “sometimes.”

Seems to me such a format is intentionally aimed at not exploring any of the participants feelings except in the most cursory way without delving below the most surface level or allowing for the respondents to expound further.

If chest binding is done properly there are no risks. And it's not permanent like a double mastectomy.

A survey 1800 females who bind about the health effects found that negative health consequences were "nearly universal." And this was among a population where only 51.5% said they bound their breasts every day.

97.2% of participants reporting at least one negative outcome they attributed to binding. The most commonly reported outcomes were

• back pain (53.8%),
• overheating(53.5%),
• chest pain (48.8%),
• shortness of breath (46.6%),
• itching (44.9%),
• bad posture (40.3%), and
• shoulder pain (38.9%) (Table 3).

Of the categories examined, skin/soft tissue and pain symptoms were most common with 76.3% of respondents reporting any skin/tissue concern and 74.0% reporting any pain-related concern.

Abstract: https://www.tandfonline.com/doi/abs/10.1080/13691058.2016.1191675?journalCode=tchs20

Full text: https://queerdoc.com/wp-content/uploads/2018/05/Binding-Health-Project-Results.pdf