Sorry, this is one of those thorn in my side things.

DAZ is the company, Studio is the application you are trying to install. DAZ also devs Carrara, Bryce, Hexagon, and a slew of plugins.

Now let Studio install where it wants; programs files, and let it install it's library where it needs it; my document. Now are you going DAZ content or Poser? Or both?

Find all your stray runtimes and content folders; I feel for you, at one time I had DAZ content in 4 different places because of using the crap installers. Sort your runtimes as you want, I personally hate a conglomerate runtime and why I dislike the studio; cluster F, "my library" folder. Which is where all your Studio content must go; unless you want to complicate it. I haven't tried to have an extrenal Studio content folder for a while so DAZ may have imporved it.

Now I opt for manual installation of content. As you have found unzipping/installing content to a "dummy" folder is quite helpful in keeping folder structure right; I hate imbeded runtimes/content folders{runtime in a runtime}. Where you install poser content to is up to you, all mine; 26 active runtimes, are on my E drive{ I have 3 HDDS totaling 2Tbites}. I leave Studio content where it wants to be; avoid battles that you can lol .

Now I can run you through organizing folders in a runtime, but I'm lost with the studio content folder.

Best advice? Clean slate before reinstall; not an easy task with Studio. Make a dummy content folder on a different drive, install to it, sort, then transfer to the main "my libarary" in documents. Take your time, verify everything, and you should be able to avoid most content issues.

I feel for you, took years of hair pulling for me to get it all sorted out. Having 2 "contentsort" folders was quite helpful. One for Studio content and one for Poser content. making sure it is all right before cut&paste/drag&drop is essential.