Guild Wars 2

I know hat gw2 doesn’t have dedicated healer and tank. I am looking for a class that will benefit from equipping supporting stats the more ( boon duration, etc )

I found that elementalist and Mesmer can tune into some kind of a “support/buffer” class , what’s your opinion ?

To straight up answer your question: mesmer.

Though if you have to ask this type of question, I have my doubts you are in any shape or form participating in any type of game content where this would matter.

Elementalists are prime damage dealers in raids and fractals, can be played as tempest healers (though druids are the go-to healer atm) and provide might next to warriors.

Mesmer is the primary support bonn share class at the moment in a group/raid enviroment.

None of this matters though unless you plan to play fractals/raids. In either case it would be way more important that you actually enjoy the class, especially with an expansion on the horizon which will shake everything up anyway.