Twitch AMD vs x264 encoder?

Stream games like Fortnite Minecraft Valorant etc. In 720p60 with 6,000 bit rate.

My PC:

Ryzen 5 2600x

an RX 5600 XT

and as RAM 1 x 16 GB DDR4 2666MHz.

What exactly is your question now? When it comes to the encoder, it depends on PC to PC, just try out what suits you better.

720p60 with 6,000 bit rate.

And further?
Can be done if you have the right upload and the hardware.

But what's your question?

Whether I should use the hardware or the software as an encoder

But what would you recommend?

Both are hardware.
x264 is CPU and the AMD encoder is your AMD GPU.

Personally, the x264 is better

As I said, you have to find out for yourself. With my Ryzen 7 2700 the x264 runs better, with my buddy with exactly the same hardware as the NVenc.