You first need to convert it to a ringtone, which is simply an AAC file that is renamed to a .m4r extension. Not sure if you can do it on the phone itself. Since you didn't mention how or where it's been downloaded, nor which file format it is, it's hard to give more specific answers.

https://www.techspot.com/news/96782-apple-expected-lose-6-million-iphone-14-pros.html

Electronic devices are not investments. They are consumer goods. Any decent phone will last several years. The vast majority of people upgrade because they want the latest and greatest, not because their phones no longer work.

Wow, how small are your hands? I have small hands, and I don’t notice much difference in size or weight between the 14 pro and my old XS. The most noticeable difference is the larger camera bump.

You can use the Files app, or just connect directly with your PC and use the normal file transfer. You can only transfer the pics in the picture roll. Pictures that had been previously added via iTunes cannot be transferred this way.

You just need a charger that allows you to use a lightning cable. I'm still using the old charger with a USB-A port (I think it's 5W) and cord from my iphone XS, and it works fine. I also got an Anker Nano USB-C charger for times I want faster charging.

If you didn’t want to lose any data, then you should have backed up the phone before things went south. That’s the entire point of backing up your data. Your best bet now is to fix the phone.