My system starts similar, but I prefer categorising by type of resource over publisher, when I have a lot of files. The publisher doesn’t hold much value to me and simply dumping everything into a single folder, even under system can become messy quickly. I sort by system, rules, adventures and sometimes by supplements or additional material like cheat sheets, when there are too many. For some things I also keep a table (or plan to create one some day, haha), because adventures and random tables might work for different systems and I’d like to remember them.