Q: When is it too soon to reapply?

How much time has actually passed since you applied? If you didn’t get picked for an interview it is probably due to a combination of experience or skills along with your portfolio.

Even if you improve your portfolio, if you don’t have the skill set or experience they are looking for, then reapplying even a year later isn’t going to help your cause. Especially if they are filtering this through an HR person rather than the ID team directly.