I kind of see your point, but only in the context of working on time-sensitive task which others rely upon. But if it is hobby/educational project, what is wrong doing things by yourself? And resort to decomposing existing solution if you can't figure out why yours is not working?
There's nothing better for understanding something rather than trying to do that "something" from scratch yourself.
I think the point is that OP is learning things about a wide variety of topics that aren't really relevant to their stated goal, i.e. solving the sensor/state inference problem.
Which, as you say, can be valuable! There's nothing wrong with that. But the more complexity you add the less likely you are to actually solve the problem (all else being equal, some problems are just inherently complex).
There's nothing better for understanding something rather than trying to do that "something" from scratch yourself.