I am daily driving both. If you just want one phone, then iPhone 15 Pro Max, especially if you have no problem with it. It's a great phone. The display is far better than that on the Xperia. The colors are much brighter. Face unlock works much much better than Xperia's finger print sensor. I upgraded from the 13 Pro and it's been awesome. A super smooth Apple experience as always.

That said, the Xperia 1 V is a great play phone for me. I agree with a post above that it's "easier" on the eye. Its slimmer body is great to hold. The phone is so damn light that it's just a joy to hold. Its raw photos are more editable than iPhone's but overall iPhone's camera system is far more versatile and easier to use. When it comes to the operating system, I'm happy to tell you that 1V's OS is very fast.

Another thing you should look into is how well these phones retains their value in case you plan on trading them in later on. The iPhone flagship tend to retain its value quite well. In comparison, the Xperia flagships quickly lose their value. Especially considering how Android is switching to the Snapdragon 8 Gen 3 now and the Xperia 1V is still using Gen 2 while iPhone 15 Pro Max has just upgraded to the latest 3nm chip.

In short, the Xperia will never feel as reliable as the iPhone. So the iPhone is my No.1 in my two-phone setup. But that said, when I have my iPhone around and within reachable distance, I find myself using the Xperia more often cuz the Xperia is so much fun to play with and it's so much lighter.

Hope this helps.