Dominick Mysterio is one of the most hated heels in pro wrestling. This is not an understatement. He was not a beloved character as a championship partner with his father, Rey Mysterio. This is because he came across as a discount version of his father. Most rookies in pro wrestling have a hard time living up to their father's reputation. He has had the skills to be a professional wrestler but his build looks like he is a cosplayer. He was not afford that trait but he has height, skill and drive to be a better wrestler. The fans did not care about any of that because of his pairing of his father.
The betrayal (or heel turn) of Dominick Mysterio was started by Rhea Ripley because she took a liking to him while trying to recruit him to Judgment Day. Judgment Day was lead by Edge (Adam Copeland in AEW) as he wanted the younger generation of WWE Superstars to learn from him. Judgment Day turned on Edge and he wanted the help of Rey Mysterio but not Dominick. This would lead to the rise of "Dirty Dom" as a nickname of Dominick Mysterio as he beat up Edge and his father.
Dirty Dom as a new generation Eddie Guerrero has changed boos into cheers
"Dirty Dom" Dominick Mysterio has been the WWE NXT North American Champion twice due to Judgment Day's help. He managed to finally pin his father, Rey Mysterio, with the help of Liv Morgan, another Judgment Day member. Roxanne Perez was recruited into the group by de facto leader Finn Balor. This was done to gain control over the group and embarrass "Dirty Dom." This has yet to happen because Dominick Mysterio won the WWE Intercontinental Championship at WrestleMania this year by pinning Finn Balor to the cheers of the crowd in attendance!
Now, "Dirty Dom" is using the "lie, cheat and steal" monkier that his kayfabe father used. Eddie Guerrero is his storyline father during his feud with his real father, Rey Mysterio. The fans are cheering for "Dirty Dom" in all of his matches to cheat to retain his WWE Intercontinental Championship as well as his AAA Mega Championship that he won from El Hijo de Vikingo a few months ago during WWE/AAA Worlds Collide in Las Vegas, Nevada.
Dominick Mysterio as a massive babyface is simple
"Dirty Dom" has to present himself as a wronged man by getting kicked out of his group, Liv Morgan has to dump him and he has to stop cheating. Why would he have to do that? He needs to do this as a underdog, main event babyface that the fans have a longing to be a WrestleMania Level main event talent. He is not muscular or strong but he is smart. clever and resourceful. His skills can be done without cheating but he has to be built as such. It will take about 2 years after he is no longer cheating and the fans must embrace that change. That is the only way that "Dirty Dom" will be the greatest Mysterio ever and a massive babyface!