Does bitrate do anything with lossless audio?

I have recently exported a video using the HEVC Main Profile setting, swapping aac to alac without making any change to the bitrate setting even though it seemed kind of low to me. I also made several audio tracks using the audio/ALAC setting (which gives a higher default bitrate of 384k instead of the HEVC Main Profile’s 256k) but since less was going on in them, their bitrates were actually a little lower. Also all of them had like bitrates of 1k-2k.

I feel like my question has a fairly obvious answer (of “no”), but I’d like to ask anyway. Does the bitrate setting do anything when you’re exporting lossless audio like ALAC? If not, why is the default bitrate changed from 256k to 384k with lossless audio options?

Bitrate does not matter for lossless. As for why the bitrate changed when choosing a different preset, that is because when you choose a preset first everything is reset to the defaults without choosing a preset and then the preset applied. Presets are relative and do not define every possible parameter of which there are many. For example, when adding a custom preset, it suggests at the bottom of the dialog that you can remove items you do not want to include. Often things like resolution, aspect ratio, and frame rate should be removed. So, presets need to have a stable base onto which they apply, and that is the default values. And 384 Kb/s is the default audio bitrate. Also, the export advanced UI is intentionally dumb and does not know to hide the bitrate option for lossless audio. The advanced UI assumes you are advanced instead of trying to be advanced itself.