!HELP! RTX 2080 max Q: Low FPS no matter what settings, all games

Hi, I am having serious issues with my Razer Blade 15 Advanced RTX 2080mQ all of a sudden. In almost all games I am suffering from low FPS (changing settings doesn't matter); I tried all I know/found, including updating all drivers, a complete clean windows re-install etc. etc. See below benchmark results which are not what they should be. Other symptoms I have (if helpful): my wifi adaptor keeps switching off after a few minutes in any game; Apex legends is unplayable due to package loss / prediction errors. Everything used to work just fine until a few weeks ago. Another issue: i suffered from battery bloating so had to remove the battery (typical razer issue), but these problems were already there before I removed the battery. Any ideas what could be wrong? Ran intel processor diagnostics and they came out fine. About to throw the laptop into the bin and buy a new one (super frustrating as its not even 2 years old). Any ideas, suggestions welcome. Full details: Razer Blade Advanced 2019, RTX 2080 maxQ, 16 GBP ram, 512 SSD, Windows 10 home, Latest intel and NVIDIA Game Ready Drivers, fresh windows install, running razer synapse, cortex in back ground, windows game mode on/off no difference. Benchmark Results (Shadow of the Tomb Raider): 1440p max setting w/ ray tracing: 26FPS, 0% GPU bound, 1080p lowest, no ray tracing: 47 FPS, 3% GPU bound