Duterte is facing impeachment threats in the House of Representatives, led by Marcos’s cousin Martin Romualdez, who is also expected to run in 2028.
She quit her Cabinet post of education secretary in June after relations between the two families reached breaking point.
Months earlier, her father had accused Marcos of being a “drug addict”, with the president hitting back the next day and claiming his predecessor’s health was failing due to long-term use of the powerful opioid fentanyl.
Neither provided evidence of their allegations.
On Friday, the vice president said she felt “used” after teaming up with Marcos for the May 2022 election, which they won by a landslide.
“It’s not my fault that we are on this road to hell,” the younger Duterte said during a two-hour news conference where she did most of the talking.
“That’s why I left the administration (because) I did not like what I was hearing there, I did not like what I was seeing there”.
Duterte remains the constitutional successor to 67-year-old Marcos.