Notebook Hardware and Upgrade Questions

This past weekend after a BIOS update, I noticed that my laptop would not shutdown or hibernate. It just immediately powers back on after the screen shuts off (essentially all I can do is restart my computer or completely turn it off by holding the power button). I spoke with a representative from HP and browsed these forums and followed all of the relevant advice to address the issue:

• rolling back the BIOS
• uncheck fast startup
• install all updates
• check for viruses/malware
• run a hardware diagnostic (no errors)
• remove all externally connected devices
• update the intel management engine interface
• check to make sure automatic maintenance is disabled
• and finally, completely resetting windows via a recovery USB that HP was kind enough to send free of charge

After completely restting windows and still having the same issue, I was told by HP that this was likely a hardware issue and I'd have to send my laptop in. I was quoted as having to pay $500 to repair my laptop (this included a 30% discount)! After reading through a number of threads on this forum, I've come to realize that there may be an issue with my laptop's motherboard which seems to occur quite frequently with this laptop. I purchased this laptop towards the end of 2017, so it's absurd that I should have to pay 1/3 of what I originally paid after only owning the laptop a little over 2 years for faulty hardware. I might as well purchase a new laptop from a manufacturer with a better reputation for reliability and fixing their own hardware issues.  

Before this happened, I loved my Spectre 15. It was incredibly fast and reliable and I frequently recommended it to friends and family as the best laptop I've ever owned. I knew that once it was finally time for a replacement, I would definitely buy a Spectre again. However, given my current experience, I don't think I'll be buying from or recommending HP again.

If anyone has any advice/experience on how to fix this issue (in a less costly manner than sending my laptop back to HP), I'd really appreciate it. 

Buyer beware.