Puberty blockers don't make you dumber, they could affect fertility sometimes but it's not a huge issue if the eventual goal is a transition anyway (which it must be for them to be given). As fully transitioned people can't conceive naturally. It's a good tradeoff.

Suicide here in Europe is not higher (in fact it's higher when not carried out die to dysphoria) but I can imagine that in strongly conservative areas bullying is very strong driving people over the edge :'(