MacBook Pro Battery Replacement Seems Bad - real bad

Since iFixit showed it to be quite involved, with glueing even, for my MacBook Pro (15-inch, 2018), I opted to have a ClickAway certified Apple Tech do the purchase of a replacement battery and doing the replacement.

(Note: Nothing here against ClickAway or the Tech. The Tech actually has a great reputation in town.)

The battery does not seem to be okay. Its condition shows as "Normal," so no bad cells according to Apple? OS Monterey v. 12.7.2. But the behavior right from the start has been flakey. I quickly reported to the Tech what behavior I was seeing.

But first, the battery info:

Battery Information:

Model Information:

Serial Number: C01514309YEF90MA4

Manufacturer: SNSYIY

Device Name: A1953

Pack Lot Code: 3230

PCB Lot Code: 30db

Firmware Version: ddae

Hardware Revision: dac2

Cell Revision: 2b39

Charge Information:

Fully Charged: No

Charging: No

Full Charge Capacity (mAh): 7567

State of Charge (%): 39

Health Information:

Cycle Count: 10

Condition: Normal

I let him know that with only a wired usb-c mouse attached, the power draw down seemed about the same as with my 1000+ cycles Mac Battery that came with the machine, which had declined a bit. But that first evening while it seemed okay - and yes, I planned on doing a number of full down-to-10% charge-up cycles to train the battery - before shutting down at about 60% I got this (your system has run out of application memory) with very little running. (I had never ever gotten that message before.)

I powered down, and the next morning I booted up and the power was at 56%. Then within moments as I curiously looked at the battery conditions and cycles (cycles were 0), that 56% dropped to 48%, and then 29%, all in the time to bring up email via browser. Then 24%, 15%, then 10% - so I hooked up the Apple power supply for charging.

The Tech replied to my email spelling this out saying I might have "stability issues," and that I should be sure to do 4 full rundowns to 10% followed by full recharges... He also said I should upgrade the operating system and free up more hard drive space (which yes, was not healthy at 15GB out of 500GB). So I had been moving large files and even various "libraries" to external SSD drives, but to my mind I'm reluctant to upgrade the OS because that becomes another variable.

I do use the MacBook a lot, and with the old 1000+ cycles older battery it always worked fine. So my logic is that simply a replacement battery shouldn't suddenly make a computer have "stability issues."

I'm up to a cycle count of 10% now, and the first 6 of those cycle were usually from a sudden drop from well above 10% to the panicked notice that "You are at 1%. If you don't connect to power NOW your computer will shut down." (Or however Apple says it up in the right corner.)

The leaps and bounds drops in short order seem to only happen when the battery is down under 50%.

Might this mean this battery was previously used and recharged up to 100% from 50% its first time out? And there's some way to reset the "odometer" on a battery? (Sold as new, this history unbeknownst to my Tech?)

Might this mean this is just a bum battery and has bad cells that the Apple OS can't detect?

Note: No evident "swelling" of the battery at all, which sounds like a really awful thing.

Here are a couple images of Usage, kind of shows the weird drops in short order:

this taken while charging after a quick drop

this showing one of the sudden 1% panic notes

Opinions? Bad battery? Maybe newer replacement batteries need new operating systems?

thx,

Rich Apple (yes, it really is "Apple")