Background
Firstly, my current setup; background to the actual question:
I use rclone for a setup I call "carry": I sync a select set of folders on my main computer to a folder called "Carry" in Google Drive in cleartext, so as to make them available to be browsed on the go. I never modify these files, treat them as read only. I have a PowerShell script that uses rclone sync and rclone copyto commands to upload these files. On Drive I also have a "Scratch.docx" file and a folder called "Workspace", which I do modify on mobile devices. The same upload script makes copies of these latter files and folders on my workstation as backup, and for easy reference. I manually commit the work on these on-the-go files to my actual notes, projects, etc.
I do this in order to avoid issues that could arise from automatic two-way syncing, having had recurring issues with multiple "cloud" and sync tools whenever I tried doing that.
This setup works well for me except, on my Android tablet, all my files being on Google Drive results in some annoying limitations. E.g., I have to use docx files for taking notes on Android because no decent Markdown app seems to support editing files directly on Drive, without requiring manually uploading after each edit, and Docs can't handle .odt files. Issue there is Docs is sub-par for note taking, especially the Android app is rather unpleasant.to use.
The actual question
I would like to be able to sync my "carry" files directly to and from Android without Drive as a necessary intermediary. Ideally I'd be able to do this over local network. I tried to figure out if I could achieve this by relying on SSH or SFTP, to no avail. Ideally I'd trigger the synchronisation from the PC, because then I could integrate this action into my script, so the same "carry" folders are sync'd both to/from Drive and Android's local storage, and without me having to remember to do it separately each time. But I couldn't find anything helpful.
Also ideally this would be over wireless network, not requiring me to plug in the device unnecessarily (plus, another thing I would frequently forget, either breaking my script or requiring me to over-engineer it).
What's the simplest way to achieve this? Is it possible to do over SFTP/SSH? Do I need to install some SSH server for the tablet? I think Android doesn't have SSH built in.