There are two types of writers: planners and not. Planners shouldn't have a problem. If you're a discovery writer. . . better keep track. I think the issue is in Web Novel setting where a discovery writer might publish what they write before finishing the entire work.
For a full book, that type of writer would finish the entire draft, and then head back and edit.
Use enough glue (meaning either smut or fluff to not let people care).
Real answer: Keep your tabs on every string of plot and knot them together whenever you can, so you don't have to keep track of every little string and only some bigger strands.