I've tried your InternalRTC_interrupts example on an Arduino Uno WiFi rev2 with negative result. No errors, but nothing happens.
Hi. Please check your Uno WiFi Rev2 to see if it has this issue:https://github.com/arduino/ArduinoCore-megaavr/issues/27#issuecomment-482302760There are supposed to be two load capacitors next to the 32.768 kHz, but on a small number of Uno WiFi Rev2, one of those is instead a resistor. If your board has the problem, you'll notice one of the surface mount components (above the metal can of the crystal in that picture) is black, while the other is a purplish brown.
Hi. Please check your Uno WiFi Rev2 to see if it has this issue...
Thank you for contacting us,In order to understand your situation better, we request you to provide us the below information:One picture from each side of your board( where we can see the defect).Invoice of the purchase.Have a nice day!Best Regards,Sravya Amirisetti.Arduino Customer Support