dead phone

Writing from my Mac as my iPhone XS has mysteriously died. Yesterday, was a hot day and I spent most of the day outside in the sun with my phone(in the shade). Last night, I was FaceTiming my family and my phone wasn't holding charge very well at 20% at this point. I plugged it in at 8% and it was staring to glitch out flash, freeze while on FaceTime. I was able to recover the screen and cool my phone down with an ice pack (as I was thinking it may be an overheating problem) things seemed to go back to normal. I continued charging and cooling and went to bed. I woke up checked my phone it was at 60ish% charge, I went to check my messages and it glitched again flashing white and very light green and then black with the apple logo. it's been dead since then. If anyone has any suggestions on how I may be able to recover the phone, if it was an overheating issue, etc? Very scared to have a software bug or anything like that don't want to lose my photos, passwords, personal info, etc.