Question regarding I2C RTCs and Device Tree Overlays

I must keep the computer’s time when not connected to the internet, between power cycles. I saw mention of a I2C RTC, and would like to know which one is preferred for use, and what software support I should use in Ubuntu Server.

Also, thank you for the Le Potato as it is a great alternative the Raspberry Pi. I appreciate that it is kept at the price the Pi was formerly.

Quite a few different RTCs are supported to be connected via I2C.

i2c-ao-ds3231.dts

i2c-ao-pcf8523.dts

i2c-ao-rv3028.dts

You can also connect them to the second I2C bus: i2c-b-ds3231.dts