There is nothing mysterious and complicated about this text in Gen 37:26-28 -
Then Judah said to his brothers, “What profit will we gain if we kill
our brother and cover up his blood? Come, let us sell him to the
Ishmaelites and not lay a hand on him; for he is our brother, our own
flesh.” And his brothers listened. So when the Midianite traders
passed by, his brothers pulled Joseph out of the pit and sold him for
twenty shekels of silver to the Ishmaelites, who took him to Egypt.
The highlighted word above is (as the OP points out) is שָׁמַע (shama) = to hear or listen.
Thus, our text contains a simple narrative where Judah suggests a plan to avoid killing Joseph by selling him to the Midianites/Ishamaelites. Thus, there is a nice little play on words here:
- the brothers listened שָׁמַע
- they then sold him to the Ishmaelites - a word that means "God hears".
The force of the text here is therefore, the brothers listened, ie, they agreed to Judah's suggestion. A number of modern versions says this:
- NIV, NLT, BSB, CSB, HCSB, etc: His brothers agreed.
- NASB, ESV, ISV, etc: And his brothers listened to him
Interestingly, if this is placed in slightly more archaic English we get closer the original meaning by saying (Brenton)
- and his brethren "hearkened". Thus it is translated by JPS and a few others.
I am at a loss to understand the KJV translation of "content" - it appears highly interpretive, unusual for the KJV but not unknown.