The Roman letter G was a modification of the letter C.

https://gizmodo.com/the-invention-of-the-letter-g-1599993086
>The earliest form of the Roman alphabet had no letter g. Instead, c could represent both the sound (g) and the sound (k). The Roman letter c was in fact a development of the Greek letter gamma. This is why c, not g, still occupies the place in the Roman alphabet corresponding to gamma in the Greek alphabet, even thought the sounds of gamma and g might seem to correspond better than gamma and c from a modern point of view. In order to to make the distinction between (g) and (k) clear in writing, the Romans developed the letter g by the addition of a small stroke to c.

Possible lead in why Madonna changed Corona to Gorona on the cover of her 2019 album Madame X.
It's just a guess, though. Interested to know if anyone else has another theory.