To help others like me looking still for this option and found this topic, What I did was simply install the opera beta version https://www.opera.com/computer/beta and that's it! I use my personal profile with the beta, and the original installation for my work profile.
I also discovered a booking.com bookmark in my speed dial today (running Opera on Mac) and would like to add my voice to the disapproval of this kind of practice. That's really unacceptable but also just weird!
Lately I've been considering switching to Firefox and things like this are a good motivation to stop using Opera.