Is my PS3 dead/is my data lost?

I have a PS3 super slim (CECH-4001B) that I purchased brand new about 7 years ago. About a week ago, I tried to power it on and it was completely dead. No red light. No power. Nothing. I replaced the power cord, the power supply, the wire that connects the power supply to the motherboard, and the wire/boards that connect to the power and eject button. Nothing worked. I brought it into a local repair shop to get fixed and they said it’s most likely gone for good, but they’re going to look at it. What’s worse: I can’t salvage the data on the hard drive because apparently it’s specifically linked to the system.

This may be wasted effort, but is there any way I can save my PS3 or at least the data on the hard drive? I read online something about using a heat gun on your motherboard or putting it in the oven to reball/reflow it (I’m not tech savvy enough to understand these terms). From what I read (and I could be wrong), this could get my motherboard working just long enough for me to boot up my PS3 so that I can save files to an external hard drive, which is my main mission at this point.

Any advice would be greatly appreciated. Thank you!