Visually hidden labels, usability, accessibility and WCAG 2.1 compliance

I'm trying to understand how visually hidden labels fit within the accessibility and the WCAG 2.1 spec. It seems to me that as long as an input has a programatically associated label (whether that be a label element or through ARIA), it is compliant.

I did find that SC 2.5.3 has a note which states:

Note that where a visible text label does not exist for a component, this Success Criterion does not apply to that component.

However, I'm a little unsure how a sighted user who uses voice control would be able to use an input with a visually hidden label. Would they simply have to guess at the label name? Are there any other cases like this where a WCAG-compliant input would not be accessible because of a hidden?

I'm hoping somebody with a bit more accessibility knowledge could help guide me on this! Any comments on the general usability of inputs without a visible label are also much appreciated.