I just looked at my amazon order (I got it last year shortly after getting my powerwalls), and it was also through a third party, not amazon directly. When ordering from Amazon, I tend to avoid third parties, but I remember being eager at the time to get "the right / best thing" because I didnt know if tesla would lower the frequency.
I got the eaton, and tested it (before tesla lowered my frequency) and as others reported it worked fine (but other things in my house didnt work fine, but that discussion is in that other thread lol). So, I contacted tesla and got them to lower it. It was pretty painless actually, but I didnt get to pick what they lowered it to, they just picked a number.
With that being said, my solar was installed by solar city, and my powerwalls were installed by tesla, so they had all the exact specs of my equipment in their files.
If I were in your shoes, I think I would purchase the eaton (I buy stuff from newegg too sometimes so im sure that would be fine as well), and still keep escalating to tesla that "your microwave is running strange, your lights flicker, and your APC battery backup units are still malfunctioning. with the frequency set to 63 hz, can you please have tier 2 re evaluate and set to 62hz or 62.5 hz)?"
They have been unwilling for most to go below 62, but I suspect you might be able to get them to go to 62.5hz. In any case I am de railing this thread, because its about the UPS devices, so I will stop now, lol.