iPhone 16 Pro Max stuck in boot loop

Before the phone went into this state is began operating slow at times, and I used to think it was just bad WiFi. Then after it failed I tried many times to reset it with the volume up/down+power with iTunes routine that everyone suggests, and that didn't work. There is no Apple store near where I live but I took the phone to three different repair shops and all of them told me that it probably needs a new board and could not be fixed for much less than what it would cost to buy a new phone.

I searched through the community posts and see that many others had this same issue with this phone, but in most of these posts the OP didn't come back to say if or how the problem was fixed. I did buy a new phone, but still hoping that I can fix the Xs Max inexpensively and wondering if its worth it. Anyone did this DYI successfully?

[Re-Titled by Moderator]