Can I still revive my broken IPhone?

First of all, my IPhone went to lots of ****. It fell many times and sometimes it's either on a hard surface or into water. But it never broke once. I remember that my iPhone 6 went through this before but i still got it to work.

Here s the problem: my IPhone was charged overnight and it was really hot (but we have aircon on) but I still used it. Few minutes passed while using my iPhone it shut down on its own and it won't turn on anymore. Nwcwetheless, my phone changed temperature and the button where you can switch to silent mode still works and vibrates. Its been a year since my home button was broken and i have been continuously using "assistive touch" to use my phone. That being said, I can't really use any methods to open my phone.

This phone holds so many precious memories! Any form of help or suggestions will help! Any help is appreciated.

The phone's probably a goner. You have a couple of possible safety nets:

If you had set up iCloud you can look for your stuff on iCloud.com, and it'll be automatically copied to a computer or new phone when you set them up for iCloud as well.

And if you've got backups enabled there should be a copy in your iTunes computer or in iCloud, and you'll be able to pick up again from the date the backup was saved.