Sorry I couldn't edit the extlinux.conf as my system is on eMMC and I do not have a SD card ready, but I will try to get one
mount -o remount,rw /flash
nano /flash/extlinux/extlinux.conf <= make changes
mount -o remount,ro /flash
reboot
^ there's no need to reboot from an SD card to edit extlinux.conf
Kodi supports output to a single screen - period. It's possble to mirror content between two connected screens, but that's all, and getting that to work when the two displays are radically different sizes will require crippling the HDMI output to the resolution of the VGA output. Add "using an AMD GPU" into the mix and even getting dual-output might be a challenge.
That's probably not the answer you were looking for .. but that's the answer 
Yes, the plan is to support SM1 (S905X3) devices in LE10 (K19).
The only way to stop that behaviour is modifying packages/mediacenter/kodi/tmpfiles.d/kodi-userdirs.conf in the build-system and then building a custom image with the modification. In our standardd image they will always be recreated on boot (by systemd not samba).
You can probably hack a delete via /storage/.config/autostart.sh but since this runs at the start of userspace boot you'll need to background the task for aa few seconds, e.g.
(
sleep 10
rm -rf /storage/tvshows
rm -rf /storage/videos
rm -rf /storage/music
)&It will depend on how the touchscreen is connected to the motherboard (HDMI, USB, ???) and whether this requires drivers?
We are not a Synology NAS forum so how you configure Hyperbackup is not something we have experience with, but it's likely you need to configure the rsync command to use; in which case you will need to know where (after installing the network tools add-on) the binary is located. If you insist on looking in /storage/.kodi/userdata/addon_data/ you will not find it. If you look in /storage/.kodi/addons/virtual.network-tools/bin/rsync (as clearly show in post #2 and hinted again in post #4) you will find it. The rest is up to you.
Is your router configured for US or DE, or another country? .. the country setting should be matched to the router.
Addon binary code will be under /storage/.kodi/addons/name.of.addon as indicated clearly in the example that lrusak provided. I'm not sure how much clearer we can make it.
If /storage/.config/samba.conf exists it is used exclusively for the samba server configuration. The sample file in /storage/.config is recreated on each boot from the embedded file so it always remains current for the version of samba we're shipping. If you base you config on the sample file, you'll get the default config plus your addiions (or removals).
The method still works and the command line instructions above are still valid. Suggest you read Accessing LibreELEC [LibreELEC.wiki] first.
Your box is booting some Android kernel .. it is not booting LE.
You can create a custom conf in /storage/.config but use an include to add content from the embedded file.
What kernel is Debian using? .. we're on mainline 5.4/5.5 now and I suspect they're still using the RK 4.4 kernel.
The only USB devices attached appear to be an Apple keyboard and a mouse. I can't see any evidence of a USB wireless device.
This is an Eminent box sold in Netherlands/Belgium? .. it's not an official LE image but loosely based on our older codebase.
Is there a boot.ini file in /flash ?
"Hi10P H264" ~35%
^ 10-bit H264 is not an official standard so although it's widely used by anime fans there is no hardware decode support for it on any ARM device that I have come accross. Most anime fans gravitate towards an Intel NUC with a CPU capable of decoding the content in software.
sudo dd if=LibreELEC-RPi4.arm.img of=/dev/diskX bs=1m^ the low-tech method for macOS and Linux
I need to blow the dust off the VM that I have used to replicate building the creator app and if I can persuade someone with a clue about macOS and Qt development to poke the code. I can't promise a quick fix 
The difference between self-building a full image and a driver add-on package is quite negligible, and IMHO the packaging with a standard package is lots easier to comprehend if you're not so familiary with the build-system. Create another driver under packages/linux-drivers and then add the new package name to the list of drivers in distributions/LibreELEC/options .. then "PROJECT=Generic ARCH=x86_64 make image" should build everything with the driver baked in. Just make sure you fork a new branch in git to contain your changes (don't hack in the release branch) and then it's trivial to rebase your changes and rebuild whenever we push changes to the release branch (new release etc.).