Windows – Access denied when writing files to network drive

Cannot map network drives using 'net use' while elevated as an administrator is the previous question, and this is somewhat of a follow-up.

So here's what I've done over the last few months:

1. Mapped two network drives as normal user (username Joey, only user on JOEY-LAPTOP, my laptop)
2. Get "Access Denied" error whenever I try to write to files on the network drive – can read and execute just fine but cannot save files to it etc.
3. Unmapped network drives, ran Windows Explorer as administrator and remapped them – this fixed nothing
4. Tried using net use, that failed, so I asked this question and received the answer
5. Mapped network drives using net use as administrator, then used takeown to transfer ownership to user Joey on system JOEY-LAPTOP (JOEY-LAPTOP\Joey)
6. Still get access denied error

I'm not trying to do anything across different computers – I'm only using my laptop. I'm pretty sure this has been happening since I wiped my laptop and reinstalled my OS.