I actually like the filesystem and its hierarchical structure. What is missing is speedy access via alternative ways similar to views in SQL where you can narrow down your criteria based on filenames, dates, and contents. Finding something in a huge collection of source files used to be very slow until I discovered ripgrep which is insanely fast.

Hierarchical structure has been criticized a lot in recent years, and rightly so as for the naive view which insists that there is One Right Way to categorize things. But the not-so naive view acknowledges that any hierarchy is artificial and ultimately arbitrary, while it at the same time asserts that it can also be useful. Think of a library: which one is more useful to your most frequent use cases, one that keeps books ordered in divisions and subdivisions of subjects on the shelves, or one that keeps books in random order? I think it is the first. You'll still need one or more catalogs and one can still debate where that book on maths for the engineer goes (maths, engineering, or text books); that doesn't mean the hierarchy of the books on the shelves is useless.