Well, rats. That was my best shot. Can you post photos of the wiring?
exactly
Hi
I saw the UsinaInfo advertisement in its DS3231 module.
What country or city are you in?
I'm from Brazil
Cool, me too.
Já comprei muita coisa na usinainfo. kkkk
Hi
I am thinking very strange about the problems you are having with these DS3231 modules.
The I2C scaner found the module adress.
0 x 57(eproom)
0 x 68 (module)
Hi
My module is exactly the same as yours.
my scanner
Scanning...
I2C device found at address 0x57 !
I2C device found at address 0x68 !
done
Using your code.
2021/12/16 (Thursday) 15:17:21
since midnight 1/1/1970 = 1639667841s = 18977d
now + 7d + 30s: 2021/12/24 3:47:27
I can see the power LED on the Uno is lit, but I can't tell, if the power LED on the DS3231 module is lit.
Hi
You're right, but if the module doesn't receive power it won't be able to see the I2C addresses of the two chips.
@Tiberio_s ,
please teste all cabels or swap all cables from arduino to DS3231.
I took a third arduino module and the RTC worked well. Conclusion: I lost two arduino modules. hard work to nothing. Thanks for attention!!
Yes, but I am grasping at straws right now.
It is a total mystery, to me, why the scanner shows good addresses but their DS3231 will not respond properly. But using the same code, our modules do.
Oh oh Ó my god.....
mystery. 
if you will thinking any solution to testing. I will ready to work.
Hi
The weirdest thing is that the I2C is working on the arduino,
as it recognizes the DS3231 and EEPROM addresses.
I suggest you swap all these cables from arduino to DS3231. Replace all with new ones or ones that you are sure are good, and test again on the Anduinos that gave problems.
Also with a multimeter measure the voltage on the DS3231 module with it connected to the arduino that did not work.
Male-female wires? Easy!
Connect them all in a chain and either test continuity with your multimeter as you wiggle the chain about (you do have a multimeter?) or put them in series with a LED and resistor across your 5 V.
If using male-male wires, connect them in a chain using a breadboard and test.