How do you think Taiwan Province accent came from?

The so-called "Putonghua with Taiwan Province accent" is a method commonly used in Chinese mainland to define Putonghua with Taiwan Province accent and Putonghua with Beijing accent (standard orthodoxy). Usually there are differences in tone and tongue rolling, and because of a few personality factors, most people in Taiwan Province Province are soft and lazy and don't chew words deliberately. In short, people in Chinese mainland emphasize the clarity and semantic communication of every word and sentence, and stress tongue curling. Mainland people's point of view: "Mandarin with Taiwan Province accent is softer and can be spoken in a lower voice, and people who speak fast are generally conjunctions." Taiwan Province people's point of view: "Chinese mainland people have a heavy tongue-rolling, and their words are aggravated, and the volume is slightly higher (to better roll their tongues)" and "Taiwan Province Mandarin" are used by Taiwan Province people to define "Taiwan Province Mandarin of modern people" and "Taiwan Province Mandarin mixed with Taiwan Province people (Fujian)". In the conversation, with a little ridicule, I described the phenomenon that the elders who used to speak Taiwanese alternately read Mandarin. Because the younger generation of people in Taiwan Province Province can't speak Taiwanese, the older generation communicate with them in unaccustomed Mandarin.