[chrisism]

Okay, yes write permissions on non-rooted Androids are always annoying in this context. So is there a different folder on the system somewhere where you actually do have write access?

Just a little background on my setup, I have a Nvidia Shield and all my media (roms and images) are on a server/pc. I mounted the shares through Android (Shield) which gives the Emulators access to the roms through normal paths like /storage/remote_share/mygames/.. etc. But this only gives you read access, not write which you need for scraping in AEL.
Kodi however, has also connected the share but through it's own smb protocol. Through Kodi you will have write access (if properly configured) over a path like 'smb://server/remote_share/mygames/'. So when creating the launcher I configure my assetpaths through the Kodi smb shares and for the Rom path I use the android path.

Although this is a solution for network shares, you might want to look in a similar way for a solution on the local machine. See if you can find a folder trough the Kodi filesystem/explorer where you have write access and use that as the assets folder for your launcher. For Rom folders you only need read access.

I'm trying to solve this same issue, and coming up short because no matter how I do this, AEL can't find any roms.  I believe I have added my games folder as a SMB network location.  I used the kodi file manager, and added a source like this SMB://MyGameFiles.  I use that as my game source but AEL still can't find roms.  Would there be any advantage to sharing that folder of NFS rather than SMB?  Is there some other solution?  I'm using a shield TV pro.

The problem is that Kodi can access files in remote filesystems. However, AEL (and most emulators launched) require that the remote filesystems are mounted so they look like local filesystems. @chrisism uses some kind of trick to work around this issue, he has told me many times but now I cannot remember. @chrisism can you please help?

Well, since we are talking about the Shield which works for me, it should be something for @Jachin99 too. Lets have a go.
So first off, no, you don't need to use NFS. The default SMB share works perfectly fine. But, you need to access the shares in 2 different ways. One way is so through Kodi, the other way is through the Android filesystem.The kodi shares are the ones you already have and know, the Android shares should be mounted first.

Mounting shares on Nvidia Shield: https://www.androidcentral.com/how-mount...-shield-tv
Remember, you can use the exact same shares from the remote system. It´s only a different way of connecting.

Why 2 ways? Well the mounts are meeded so that other Android apps (like the emulators) can actually access the rom files, since they don't use the build-in filesystems from Kodi, but that from Android.
But the mounted shares are always readonly, so you still need the Kodi smb share so AEL can access and write all metadata (nfo's, covers etc).
When setting up your launcher, make sure that you use the Android mounted shares when setting the path to the ROM folder and use the Kodi SMB mappings when selecting the asset folders.

Good luck, let me know if it you get it to work.