וַיָּ֩שׇׁב֩ בַּיּ֨וֹם הַה֥וּא עֵשָׂ֛ו לְדַרְכּ֖וֹ שֵׂעִֽירָה׃
So Esau started back that day on his way to Seir.
Genesis 33:16 (Revised JPS, 2023)
When Jacob and Esau part ways, the text states that Esau heads to Seir. It doesn’t specifically state that he went alone, but the rabbis note that the previously mentioned “400 men” aren’t mentioned again.
Because Esau represents “a tilting towards the perishing,” it would be significant for the 400 men to part ways with him as well, and perhaps the text would say something about this.
The rabbis note that in 1 Samuel, there is an odd mention of David striking back against the Amalakites (descendents of Esau), and this strange inclusion of 400 men who escaped the slaughter.
Then David attacked them from twilight until the evening of the next day. Not a man of them escaped, except four hundred young men who rode on camels and fled. So David recovered all that the Amalekites had carried away, and David rescued his two wives.
1 Samuel 30:17-18 (NKJV)
Yes, the event in 1 Samuel and the event in Genesis 33 are far removed from one another in time. If you know that Torah was written/compiled/edited during the Babylonian Empire, it starts to make more sense. The text is there to teach us something, not to record history.
There is a lesson here.