m15 R6, (i7 RTX 3070) constant performance drop and screen tear

I purchased my Dell laptop around two years ago and have faced consistent performance issues. Having Dell's Premium Support Plus for three years, I've had my motherboard replaced at least five times, yet the issue persists.

Every time my motherboard is replaced, the laptop works fine for a while. However, this time, the recent replacement hasn't resolved the issue. I've been troubleshooting for months with no success. I'm unable to play any games as they run at very low FPS, with screen flickers and random freezes that drop my FPS to as low as 20. And because of this I've noticed that my ram has been running higher than usual as well. I've tried to escalate my issue, but Dell has informed me that they can't offer anything beyond certified hardware replacements. My support will end in March 2025 and I'm worried that my laptop will become unfixable after that.

Has anyone else experienced similar issues or have any suggestions on what I can do? Any help or advice would be greatly appreciated.