They are being asked the wrong question.

The most important question they should be asked 20-30-50yrs down the road is "Was it worth it?".

Of course they are happier in the short term.

Bodybuilders who use steroids are instantly much happier with themselves that they were before using steroids. The positive effects to their body image are euphoric. However, following up with them decades later, most are likely to say the negative side effects to their health and lifespan were not worth the short term positive effects to their body image.

We are way too early in this experiment to know the answer to that question specifically for trans patients, but the answers from bodybuilders who are using very similar hormonal medical treatments give us a hint.