Do phones come out on 8849 before Unihertz? Also a question about battery problems.

I read a comment from the official Unihertz account saying that 8849 (their subbrand) released the Tank 2 before the main Unihertz brand.

Can someone explain what the situation here is? I want to get a Tank 4 Pro, and I see it is also only available from 8849 but not the main brand. Why is this? Is there some complicated thing going on?

I would have expected Unihertz to get the first release on Aliexpress, and 8849 later gets an export model or something.

Is there any difference, especially in terms of support? After seeing the battery problems with the Titan 2, I'm having second thoughts. I searched for battery problems, which is how I found that comment, and I feel like they might be more common with this brand than others.

Could the reduced battery size of the Tank 4 line compared to the Tank 2 and 3 be the way they fix the problems? I wouldn't be surprised if a 20k+ battery is inherently harder to do right, and dropping it to 10k+ is an actual solution.