@sgunhouse, @yanta I googled more about this "preinstall data2" and found out it is an adware, not a malware, and I just remembered that a year back I did block this app's notifications because it was spamming random ads on my notification bar, it all makes sense now, I'm impressed this app found a way to annoy me again 1 year later by other means, I decided to force stop it and deactivate it yesterday, opera didn't open itself ever since, I guess it's solved.
Thank you two for helping
@samseb Not only you, some of other people also experience it. Anyway do you tried to clean install the opera mini? Maybe it fix the problem, on the other thing, opening private tabs not working for now, I don't know why, it just crash after changging to private tabs on anrdoid pie