Desperate Search: How to Recover a Sunken iPhone 15 Pro Max from the River

I sank my iPhone 15 pro Max in the river. yes guys, we were kayaking again and as you can see, I dropped the backpack from up there open here and I thought My iPhone is in there, all the electronics that were still in it, Actioncams, all flown into the water. luckily I could still fish it out. only I then noticed, My iPhone was also gone. now i have quickly blocked this, Location find it of course not when it’s under water, Apple Pay everything locked, my data is gone et cetera. and I knew it was in my pocket. I thought I had it here perhaps already lost before, but luckily I filmed with the actioncams and you see, the iPhone is still hanging in your pocket here. of course we searched everything, My colleague was swimming around like that, you only saw his hat once, but we just didn’t find it anymore. but now that I see it in the video, it must be in here somewhere. the question is, how do I get it back? I have a waterproof metal detector, I have a magnet, I don’t know what to do. People please help me, i am just so right.