By 2030, New well-paid jobs ______ available. ("will be" or "will have been"?)
I'm not really sure if will have been is the right answer here. I mean this isn't a completed action so wouldn't "will be" be a more fit answer?
For your example you probably want to use will be. This refers to to a point in time which is in the future relative to now - in this case the year 2030.
Will have been refers to a time, which is in the past relative to a time in the future.
By 2030, new well-paid jobs will have been created in many sectors.
In the example above the jobs do not yet exist, implying future tense, but their creation will already have happened by the time we reach 2030, so we use future perfect tense.