1. So which is it? Dhejne is worthless or miscited? I note you provide no argument against any of the peer-reviewed publications.
2. Regret rate is not nearly so important as things like, oh, pubertal bone mineralization or IQ gains unrealized, increased risk of fatal cardiovascular events, but those are more from cross-sex hormones than surgery. While no one builds their self-identify around a knee replacement, sex-trait modification has the rather unique problem of co-administration with hormonal supplementation, which can absolutely impact subjective experience.
3. Look at those counties--you don't have to read beyond the titles: Sweden. Denmark. Finland. If trans-identified people face social ostracism in Scandinavia, widely considered the most socially liberal and accepting societies in the world, where do you think they might not find a society that can be blamed for their failure to improve after surgical interventions?
Finally, the burden of proof for the effectiveness of sex-trait modification surgeries on those who advocate that the risk is worth it. It's unmet. It was always unmet, because the original Dutch studies never disclosed the loss of a participant to suicide.