Hardware encoding only available on VBR setting. (Mac M1)

2-pass encoding is a computed thing, totally ... so "hardware" encoding is never available for 2-pass encoding. And by 'hardware' this means parts of the CPU, NOT the GPU use.

That's also confusing ... as the phrase "hardware encoding" is used for two very different things.

On H.264 encodes, this phrase appears in the Summary section of the Export dialog ... and it refers to whether or not the CPU has the extra specially-designed H.264 computing hardware inside it. This use doesn't have anything to do with the GPU use.

OR "hardware only" can refer to GPU work on the effects within Premiere ... which only uses the GPU for things on the "GPU Accelerated Effects List" (search for it) such as color changes, changing frame-size, Warp, that sort of thing. And doesn't have anything to do with H.264 encoding.

Neil