OnePlus 12 is a good overall phone. I first started using OnePlus 7T and enjoyed the smoothness of Oxygen OS and built quality.
I replaced my OnePlus 7T with Realme GT 2 Pro 2 years+ ago. Recently, experienced the infamous green line issue after an OS Update. Realme refused to replace/repair the screen for free as the warranty was over. I got the OnePlus 12 to replace it. Didn't regret the decision.
The only thing that I am getting used to is the curved screen. If given a choice, I prefer a flat screen over the curved screen for my OnePlus 12.