Up until the early 2000s I used to compile my own kernel, carefully selecting only the options that I needed.
Then I realised that I wasn’t saving memory, because almost everything was a module anyway.
Is there any actual benefit to using a custom kernel on consumer hardware that’s supported by the stock kernels?
Actual benefit? I’d say code not compiled in is code that cannot be abused.
There are also more obscure benefits - like getting more familiar with your system.