It's a relatively small niche. NVIDIA won't beat AMD at the embedded space because they just don't have a CPU, so they can't make something like the Deck has.
If we do see NVIDIA in the handheld space, it'll be either a full SOC that only goes GeForce now, or they'll team up with Intel for a prosumer device, which will probably run Windows.
The Linux market is growing, but it's also quite small. NVIDIA mostly cares about AI these days, so they're far more interested in the data center and probably won't dedicate many resources to anything else, other than Windows gaming, which is a biggest.
It would be nice, but Linux gamers still have options. AMD is tried and true, and Intel has a good track record for Linux support, so either of those would be good options. Unfortunately, this means you're better off in the bottom too middle of the market, as top of market is still dominated by NVIDIA.