I note you don't tell me how my answers fell so short, so that I may clarify--no matter, I have other arguments.

Your god, who you trust to know all the facts of the universe, was okay with slavery. He didn't say "This is a terrible thing that we have to deal with for a few years, but will go away eventually." He didn't say "Treat your slaves as well as you would your neighbors, though they may work for you."

No, he explicitly allowed abuse to be inflicted on a slave, so long as they don't die:

Anyone who beats their male or female slave with a rod
must be punished if the slave dies as a direct result,
but they are not to be punished if the slave recovers after a
day or two, since the slave is their property.

[1]

So if you beat your slave so hard they die, you too can be beat--but if you beat them just short of death, and they're walking about in a day or two, you're off the hook. How is that fair? How is it in any way just and moral of this god to allow his followers to be so cruel to these people who have no recourse?

So even supposing that your argument--being surrounded by other slavery-endorsing nations made holding slaves morally permissible in the Old Testament--your god still allows horrific things to be inflicted amongst these people treated as property, so long as they don't die. So, best case scenario, he doesn't even do the minimum of saying "sure, have slaves, but treat them well."

Morality does not scale relative to time period. Slavery was always horrific--it wasn't that it slowly began to become morally-bad as time went on, it was always, always bad, people just chose to put profit over human rights for centuries. Eventually we came to realize the pain and suffering we were inflicting on people (and those people gained enough combined force to actually threaten those abusing them), and we changed our ways and laws. This doesn't mean that morality suddenly changed and slavery used to be okay, but now was bad, and people updated the laws to reflect that; no, people realized the things they were doing were indeed horrific, and changed their ways.

In the Bible, this is not the case--and I would hold that an all-powerful, all-knowing god, who can see all of time, would know that slavery would be immoral--regardless of WHEN it occurred. I think it's insane that some Christians just shrug and say "Well that was then, this is now." The lack of self-agency in such an argument disgusts me, and simply lengthens the tail on such flawed morals. That is, where they aren't actively participating in such things.

From "A People's History" by Howard Zinn:

In the year 1610, a Catholic priest in the Americas named Father Sandoval
wrote back to a church functionary in Europe to ask if the capture, transport,
and enslavement of African blacks was legal by church doctrine. A letter dated
March 12, 1610, from Brother Luis Brandaon to Father Sandoval gives the answer:

"Your Reverence writes me that you would like to know whether the Negroes
who are sent to your parts have been legally captured. To this I reply that
I think your Reverence should have no scruples on this point, because this is
a matter which has been questioned by the Board of Conscience in Lisbon,
and all its members are learned and conscientious men. Nor did the bishops
who were in Sao Thome, Cape Verde, and here in Loando--all learned and virtuous
men--find fault with it. We have been here ourselves for forty years and
there have been among us very learned Fathers . . . never did they
consider the trade as illicit. Therefore we and the Fathers of Brazil buy these
slaves for our service without any scruple . . . ."

So I'm afraid that even your original statement, "Christians do not advocate for slavery. Many laws of the old testament were for the jews living at that moment of human history," is demonstrably wrong in the deepest way.

[1]: https://www.biblegateway.com/passage/?search=Exodus%2021&ver...