Couldn't we use varanda as well?
Yes absolutely. It's understood in all forms of Portuguese and it's the literal translation in EU-PT where "sacada" is not used.
The hint for "balcony" doesn't show "sacada". It's been reported.
Why is this "quero" and not "quero de"?
The verb querer doesn't require a preposition to introduce a direct object.
as opposed to gostar, precisar.