2
That European countries are generally reluctant to endorse gender reassignment treatments due to insufficient evidence
That is at least half-true. E.g. Sweden did mostly stop using hormones with minors (iIrc under 16). Namely Karolinska - one of the most reputable university clinics in the world - did and he country's health advisory board published restrictive guidelines. Reluctant really is a good word to describe the current situation, puberty blockers are still used, but only in few cases. Afaik there's a few similar developments in other countries but I am not sure it's Europe in general.
https://www.france24.com/en/live-news/20230208-sweden-puts-brakes-on-treatments-for-trans-minors
That there are no large scale studies / reviews that find good evidence in favor of gender reassignment treatments
A study from Karolinska (well at least the press release for it) also complains a lack of data:
But I'd say the lack of data is to be expected. The number of people seeking gender affirming care skyrocketed in recent years. So we obviously don't have long-term data that applies very well. People who already came out as transgender 30 years ago may not tell that much about people who do now.
So we unfortunately have a situation where we have to make decisions under uncertainty. But that doesn't change that not doing anything can be worse than doing something you're not 100% will work.