Project folder with sub-folders?

I have a project folder with all projects in their own folder; this is standard behaviour.

However, I have a bunch of topical project folders, like ESP projects, MQTT projects, CAB bus projects.

I’d like to have sub folders named MQTT, ESP, CAN in the projects folder and then move the ESP_a, EPS_b, ESP_C folders into the ESP folder, and do the same with the the other mentioned above.

One could argue why not try, well, my environment (after a few hick-ups) works, and I don’t want to bugger it up; hence, me asking, maybe someone tried and can comment.

Also, could I just move them in Explorer, or do I have to create new project folders?
How do others manage lots of projects?