The biggest downside of ditching Windows is losing that comfort zone where everything just works without thinking about it. But if you're cool with putting in some effort to learn new stuff, Linux will feel way snappier right from the start.
Since you've got an Nvidia GPU, I'd definitely go with CachyOS - it's been my best Linux experience for gaming and daily use. The Linux community respects it too: https://cachyos.org/
For your setup specifically, you'll probably like how much less space Linux takes up compared to Windows, plus it's way lighter on system resources so your older hardware should perform better. Gaming works surprisingly well these days thanks to Proton, most stuff just runs.
You could dual boot first to test it first without committing. CachyOS would be perfect for what you're doing.
While I can't find any source to back up my claim that it certainly drains some amount of battery, can you provide any evidence that it doesn't impact battery life? Given that GPS uses significant processing power
Matrix is open source, should give that a try,
it could be a bit more user friendly tho