I just did. I'm British but live in the USA. we just went home for a few weeks holiday and took my drone. No issues what-so-ever bringing it back into the USA.
You often state that registration = confiscation, but it's still incorrect.
And your insistence that if further imports are banned, your drone will be confiscated is naive and extremely unlikely to happen.
You did not mention your altitude which may help determine the best course of action. I have had a very similar incident and it does happen too fast to make proper decisions. Wasn’t enough time for a prayer.
You noted the following:
"when I looked away from the plane and back to the drone, I couldn't immediately spot it again"
Maybe keep your drone at a distance where it can easily be spotted? Had you known exactly where your drone was located, you...