3900x vs 3950x
3900x vs 3950x
Focus mainly on your graphics card performance since those games will strain it more than the processor.
I wouldn't recommend boosting Ryzen's speed. It's not worth the effort and could actually hurt game performance since overclocking won't raise clock speeds much. For your needs, the 3900x is sufficient. If you're using an NVIDIA GPU, consider pairing it with NVENC Encoder so the main processing happens on the GPU while streaming.
For streaming and gaming, even a 8C/16T CPU works fine. When you rely on your GPU for encoding—like using an Nvidia GPU with NVENC instead of H264—your CPU gets less strain. Photoshop mainly needs single-core processing, though video editing can use multiple threads depending on the tool. Unless you're doing intensive video work constantly (beyond gaming, streaming, or photo editing), the 3900X is likely unnecessary. Your situation doesn’t justify the higher price of the 3950X.
The 3950x is not worth the investment since the 3900x already provides sufficient performance for any workload.