I'm just thinking of the next poor person who installs LE11 and says what i said "why isn't "enablehighqualityhwscalers" working
You're the first person to notice since LE11 shipped and nVidia active-install numbers continue to decline over time (we've been telling people to avoid nVidia cards for years now) so the chance that someone else spots the problem is fairly low.
Any suggestions.
Read the message on the screen?
LE10 and earlier use NTFS-3G via FUSE to mount NTFS drives. LE11 switched to new(er) in-kernel drivers so you'll see a significant increase in file read/write performance. However the in-kernel drivers appear to be a little more enthusiastic about flagging issues; hence the change in behaviour that users are seeing.
LE normally does fsck before mounting drives but there is no fsck.ntfs utility to do this (ext2/3/4 etc. use /usr/sbin/e2fsck). In the past there was an fsck tool from NTFS-3G and I'm wondering if we might need to restore the package; not to switch back to the older driver, but to build and pick the fsck tool to the image.
Kodi allows drives to be selected and unmounted in the file browser, but otherwise the GUI doesn't have an easily accessed option and you'd need to create an unmount-all script and then map the script to a custom remote keymap.
Team Kodi didn't decide on a 20.3 release yet, but it would be good to send the PR in case it happens (the idea has been made). It's always better to merge patches upstream instead of adding them downstream at the LE repo.
Error code 110 is "ETIMEDOUT" i.e. connection timed out. I'm not sure knowing that helps though.
131 Linux Error Codes for C Programming Language using errno
Kodi doesn't build binary add-ons; that's left to distro maintainers to build/package them as needed for their users; so LE builds them and makes them available from our add-on repo.
The SD card will be /dev/mmcblk0 so as long as that /dev/device exists you can test writing with "dd if=/dev/random /dev/mmcblk0 bs=1m" and the OS will write random data to the entire card. It will take quite a while (larger card size = longer time) but if there are problems with the card (or reader hardware) it'll throw errors and hang/halt/barf on the task. To state the obvious; this will trash whatever data is currently on the card 
AirPlay etc. require the router to replicate broadcast traffic that advertises the service on both wired and wireless segments. Some routers do that, and others don't. If the RPi cannot see the WiFi SSID; common reasons would be the SSID being hidden (ConnMan cannot see something that is not being broadcast) or the wireless regdomain might need configuring to align the radio properties.
It's a while since I shipped my Slice to another LE dev, but CM3 was a nice bump over CM1.
In the absence of debug logs I'd make an educated guess that the keys that underpin the S in SFTP changed on the Synology side and while FileZilla is configured or defaults to ignoring that Kodi will probably flag the mismatch and fail. I'd have thought that kind of thing would be relatively obvious from logs though (although I never used SFTP for anything). See if clearing /storage/.ssh/known_hosts (or the old entries for the IP/FQNDs of the Synology target) makes a difference?
So... I'll try this N100 fanless adventure, for 235 euros... It's more than 150 euros on RPi 5, but not so much (especially if it lasts 8 years also)... And the N100 is more future proof...
Estimated shipping in December 2023 as long as they accumulate enough backers. Dates on Indiegogo are often a little optimistic so good luck with the purchase
If it was already installed (and thus appended to $PATH at boot) the removal didn't alter $PATH in your current session and hence it should have been disoverable after reinstalling. If you uninstall > reboot > install .. it won't work again until another reboot or logout/login.
btw, this is the add-on icon.png that I created for a previous Argon addon attempt, based on the normal LE house-style/template.
Normally the "Disable SSH Password" option is used after configuring certificate authentication instead. So turn off the disable to allow SSH passwords again. If necessary (re)set the current password: there is deliberately no need to know the current one, it's just overwritten.
You need to reboot or logout/login after installing the binary add-ons else they aren't in the $PATH and can't be found.
I was wondering if the box was finding an older /storage partition from the older install, but blkid shows none of the partitions that exist on eMMC have partition GUIDs or names that would match so that's a dead end. And I meant "ssh" before, so that's not an issue.
You did mention running a custom OS and not the stock one, but I don't really see how that could impact on Linux since the box is still booting (vendor u-boot) and hooking it to boot LE from SD card. Both stock and current OS are likely to use the same u-boot code.
There's a pattern where services are waiting for things on the SD card second partition (/storage) to become available which results in some messages in the journal log, and the overall speed of boot looks a little slow to me. However I'm used to looking at logs from devices that boot from faster eMMC so that's just perception, and my boot logs also show similar messages: and ultimately /storage does mount and things do continue. I can't explain why the sshd.conf file hasn't been created automatically, but perhaps related to the second-boot failure to mount the storage partition. However boot scripts should still detect its absence on third boot and create that conf; it's not a one-time/first-boot only thing.
In short, I'm a little stumped 
