I dont buy my bikes on aliexpress and i've had several warranty issues / goodwill instances when my counterparts did the right thing. I've had 2 or 3 warranty / crash claims with Farsports, i've had velobuild send me their updated C rings free of charge, i've received wheels that were centerlock after ordering 6 bolt and received adaptors free of charge. I've had a derailleur replaced free of charge & received a bunch of freebies.

Long story short, there's more to dealing with chinese counterparts than aliexpress & assuming no warranty coverage. I'm the highest tier on aliexpress and usually (not always) they are helpful. I had a bad experience with Alibaba, they clearly gave no F about me, that was disappointing, but i'm not going to cry about it, after all they were sticking to their T&Cs.
In fact 2 weeks ago i ordered via aliexpress a replacement crank arm for cheap. I shouldn't have paid for it, but this seller is a dick and i'll do my best not to work with them again. Either way it should save my ass for cheap enough.

I guess my point is: build relationships with sellers you learn to trust. It's so much easier than it used to be to have clear discussions with them. Either they speak decent english now, or they use translation software that actually works. It used to be an uphill battle to make yourself understood. Now i feel i can ask very detailed questions and i usually get spot on answers.

Last: the vast majority of people still assume that if it's unbranded and chinese, it's poor quality. I have friends who to this day will not use an unbranded chinese bike out of fear of death. Sadly (?), some of them are actually highly educated people with engineering degrees placing them in the 0.01% of the population. Others are just Luddites. Which ties back to Factfulness, in fact.
Most of this forum exists to navigate issues around oval holes, unfaced brake mount surfaces, out of tolerance interfaces, and structural integrity of parts. Together, usually referred to as QC. Aka, quality... Aka, who to order from to minimize the chances of ordering a dud.

All 4 of my EDS OX derailleurs have the removable batteries.   To date, the removable batteries last a long time, over 600 miles of riding for me with lots of shifting.

OTOH: Weird things have been happening.  Yesterday, I went out on a snow ride on a bike I haven't ridden it about a month.  The bike was shifting OK, but I though that I would swap to a charged battery to be sure that the battery on the bike might be low on charge.  I swapped to a supposedly fully charged battery.  It wouldn't shift. No lights.  Swapped to another battery.  This battery didn't shift the derailleur either.  Put the original one back one and rode, leaving the other 2 on their chargers.   Then swapped one of the freshly charged battery onto the derailleur and it worked.  Now I am wondering why 2 fully charged batteries were drained of power after sitting around on a shelf for a month after last being charged. 

Regarding the fixed battery.  I am sure you can put a routine in place where you use your Wheeltop app on your phone to check the % charge / # of shifts left.   If you see the battery is below your charge comfort level, you can top it off. 

I wonder too, if the magnetic charging cable charges the battery while the derailleur is in operation.  One could secure the charge cable to the frame and use a battery bank to charge the battery while riding.  (Anyone test this?)