Here I have to disagree, respectfully. When I toured the skinning shed in Zimbabwe on my operators "lower quality elephant area" concession I admired the three sets of tusks from the client that just left the week earlier than my arrival, their skulls still next to the shed mostly buried. All three sets were in the mid to high 60s. I was there very, very late in the season so the rains were pushing the elephants into Botswana and there numbers were becoming scarcer by the day. The largest we saw in three days was one 53lbs on both sides while I was there.
Any advice of how great Botswana is for elephant is likely talking about a race of elephants that is migratory from the area of Hwange/Matetsi area of Western and Northwestern Zimbabwe that flows through into Botswana. Arguing that one country is good and the other is not is subjective, as the elephants of this variety are crossing the national boundaries every year.
I recommend Zimbabwe over Botswana for a few reasons. 1.) Price. Zimbabwe is going to be less expensive than the insane prices in Botswana caused by very affluent people flocking to the limited quota hunting that just returned to Bots after a decade of lockdown. 2.) Zimbabwe's accommodations and logistics will be better on the whole because they have been operating every year rather than getting back into the game and making roads for the first time in a decade or more. 3.) US importability. The "case by case basis" determination for USFWS approval to import ivory is very strict. Ultimately, years of financial reports showing ongoing commitment to the local community, sources and uses of funding, hiring from the local community, humanitarian relief by drilling wells and donating to schools, year over year game counts showing healthy numbers, annual spend and results of anti-poaching efforts, financial benefit to the local community, and finally that the death of the individual elephant was a net-benefit to the survival of the species overall.
Point #3 above is going to take years of historical track record in arrears to make for a viable US import application. With Botswana's absence of dangerous game hunting for more than a decade, they will not have the robust data set for these concessions to satisfy the USFWS requirements for case-by-case basis approval of a hunted elephant in my opinion.