This should get you started:
Note that not all parts are relevant for accomplishing what you need. His general mount settings + Plex settings (especially scan settings) would be the main parts to look at.
I can't confidently answer you about Plex-spesifics since I don't use it myself, but I certainly help you with the basic setup stuff. Animosity currently does not use cache in his personal setup. I think improvements to the VFS-layer + correct Plex scan settings made it largely redundant.
But before I start providing guidance on how to do the setup - you should at least attempt to follow the basic instructions in the documentation yourself. Most of it is pretty simple and I'd just be repeating it for you. Much better if you go try it first, then return to me with any questions you might have.
(1) Download rclone. For Linux I'd recommend you use the "script to download and install". If you use a repository then be aware they are often woefully out of date. Better to just install it straight from the source IMO...
https://rclone.org/downloads/
(2) Set up your Gdrive remote, instructions here:
https://rclone.org/drive/
(3) Set up your encryption remote, instructions here:
https://rclone.org/crypt/
The part people sometimes get confused about is how to link/stack your 2 remotes together (hint, point your Crypt to point at your Gdrive remote name). Ask as needed.
(4) Mounting the final product to a virtual drive so Plex and other programs can access it.
https://rclone.org/commands/rclone_mount/