I’m told that the literal translation of “we saw his star in the east” was “we of the the east saw his star and have come to worship”. In other words they(the wisemen) were east of Israel and looking westward.
That still has Jesus born in 7 BC.
Another point, the Grand Conjunction was a very predictable event, every 20 years, and astrologers and astronomers (same MOS back in the day) were perfectly aware of it. It wouldn’t have been seen as anything much out of the ordinary.