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The battery cannot be checked from anywhere. I have yet to encounter a PC that would offer a voltage reading on the CMOS battery.
It is highly likely the article you link is low-quality blog-spam, possibly even generated by ChatGPT.
You can check a reading of the battery voltage with HWiNFO: https://www.hwinfo.com/
Here's an example of it, from my motherboard:

My MSI B450 Tomahawk Max uses the chip Nuvoton NCT6797D, which can provide this information.
In the linked manual, you can search for it on page 129.
I can't vouch by the accuracy of it, but, it should be in the ballpark.
You should check that it is at about 3.3 volts.
Those batteries last about 5-10 years, from my personal experience.
If your PC is around that age, you might want to think about replacing it, even if the reading is "good".
Keep in mind that some laptops use the charge of your battery as the CMOS battery, to keep things running.
If you discharge the battery entirely, you might see that the time was lost or is wrong.
Before considering to attempt to open the laptop to check/change the battery, you might want to check if it even has a battery, in the laptop manual.