Question about lithium-ion replacement phone batteries.

[RANDEAG]

So I just got a renewed s10+ which is great except the battery health is about a 3000mAh capacity down from 4100mAh. I was looking into either battery pack cases for it, or just an upgraded replacement of 4500mAh+ batteries. I found a replacement battery that is supposedly 5200mAh, however there is no reviews about it and in the description it states:

"Please Note：

At the first beginning, the battery will drain quickly, this issue is caused due to the li-ion of a new battery is unstable, it will become normal after long-term use. Please full charged first if phone can not turn on.

To use the battery longer, please use up all the energy of battery until your phone shuts down automatically, then charge it for up to 8 hours, repeat this 3-5 times, thus the battery can be reached the optimum effect of using."
https://www.amazon.com/SHENMZ-Samsung-Galaxy-S10-Plus/dp/B097D9WBFJ/ref=sr_1_4?dchild=1&keywords=s10+plus+battery+5200&qid=1627008239&s=wireless&sr=1-4

So I wanted to ask, is this a legitimate reason that a new battery might drain faster and it will fix itself? or are they setting up and excuse for it to be a bad battery?
I tried to Google it, but couldn't find anything no matter how I formatted the criteria. 

If anyone knows, I would appreciate the input. Thanks.

[Biohazard777]

13 minutes ago, RANDEAG said:

So I wanted to ask, is this a legitimate reason that a new battery might drain faster and it will fix itself?

Ever owned a new laptop / phone / camera? Do they drain faster at first and then "become normal after long-term use"?
You don't have to know anything about battery technology, just need some common sense to smell the BS. 

[RANDEAG]

lol yeah obviously, but I didn't know if maybe phone and laptop companies cycle the batteries first before people use them for this reason. 

[SorryBella]

5 minutes ago, RANDEAG said:

but I didn't know if maybe phone and laptop companies cycle the batteries first before people use them for this reason.

Nope, its just to see if the battery fits their capacity tolerance because there are no identical batteries.

[RANDEAG]

gotcha, tyvm