"Autogain" is a topic that is often mentioned on the WiiM forums - see e.g.
this post for my perspective on it.
IMHO the way WiiM implemented automatic overload protection with an output limiter is sensible, but it won't satisfy everyone.
They opted for a solution which doesn't decrease overall level, but instead compresses peaks which go above 0dBFS. For users who use the digital volume control of the WiiM device itself this is a perfect solution, since peaks won't ever approach 0dBFS (unless volume is set to 100%).7
But there are also users who lock WiiM volume control to 100% and control volume somewhere downstream (e.g. external DAC or amp). Those users will have a much higher chance of hitting 0dBFS, so any boost done by pregain, EQ or RoomFit could trigger the built-in limiter. For those users autogain would potentially simplify gainstaging.
Luckily WiiM also provide capabilities to manually adjust headroom for overload protection via input pregain and volume limit features. That way we can avoid triggering the limiter even when using EQ boosts and volume set to 100% - and we have control on how much we want to decrease the level.
The IMO sorely missing component is clear documentation with simple instructions that any user could follow, but which take a holistic view of the signal processing pipeline. And possibly some improvements in UI/UX to make configuration simpler and more intuitive.
That all being said, the users who are most likely to run into issues are those that try to chase "bit-perfect", but who also experiment with DSP (possibly not realizing that those two by definition exclude one another).
This post covers my perspective on bit-perfect
