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?
Normal user? Extremely rarely would you need to build the kernel. Distributions design their options to fit most use cases, and you’ve observed the extensibility through modules. The kernel itself has moved towards runtime configurable options for your convenience over time, such as with
Where in the past changing the preemption model would require a recompile. Ultimately, this is a good thing; it makes your life easier and you can get better support for a common kernel if you need to debug.
It does happen though if you need special hardware or if you’re picky about specific kernel features. For example, I’ve used kernels that don’t have built-in support for memory compression. Need is a subjective term, and I felt that was a configuration option that I needed because a memory upgrade was not an option. I would argue there was a point to that effort. Considering that you phrase your question as asking about normal users, then no, I would say that’s rarely beneficial, might actually be disadvantageous because you won’t receive as much help debugging problems from your distribution, and generally you can achieve your goals by tuning runtime kernel parameters anyway.