Well, I have decided to return my iPhone 12 Pro Max instead of replacing it. I had a dead pixel, so I had to send it back, and instead of waiting for a replacement to arrive, I have decided to try out the mini, and I'm in love with this phone.
Having used iPhone 12 Pro for about a week, 12 Pro Max for 5 day, and mini for a couple of days, I can say with confidence that the mini has almost identical camera (the main decisive factor for me to go with Max at the the first place), with only one a big downside being the battery life. I wouldn't say that it's bad on the mini, but the 12 Pro Max battery life is just so much better.
In any case, I have 12.9-inch iPad Pro, which I plan to use more for tasks, which require bigger screen, and mini will serve me as a 'boring phone'. Both mini and Max are amazing, so no matter what you get at the end, I am sure you will be happy.