The basic idea is to create a /storage/.kodi/userdata/keymaps/remote.xml with key mappings. For context menu at blue button it's:
<keymap>
<global>
<remote>
<blue>ContextMenu</blue>
</remote>
</global>
</keymap>A full list of Kodi key mappings can be found here: Click!
There isn't a kodi.log file on the microsd card.
You can activate logging (log level 1 or 2 will do) by creating an advancedsettings.xml.
You probably have to add an udev rule: Click!
You can attach the HDD to the RPi, if you put it into a case. RPi has good software support, which is important to be future-proofed. I think an RPi is a minimalist solution.
I don't have anything against old hardware, I just wouldn't invest more money into it.
If Full-HD is OK, then an RPi3B+ will do for most streaming services.
Really? That processor is more than 10 years old. 
If you invest into a mini-PCI-e graphic card, you will still suffer from slow data bus. That's a bottleneck for modern media formats.
Better use your money for a new Intel NUC or an RPi4B, depending on the media standards you want to play.
I understand however could you then not restore those two posts and edit to remove all the links or all but the first link?
I spent some time putting the text together and the posts were just deleted by so I can not restore and edit them myself.
Yes, that's fair. I've been restored your two posts, and removed most of the links.
We are skeptical about fresh users, who post a lot of links. Just skip the links and post what you have to say.
FLIRC should work without issues on LE. You'll find results like this, if you use our search function.
I can access the services without problems on my RPi. The error is related to SSL certification. Maybe you have to change router settings:
2019-04-11 19:29:11.046 T:2676839280 DEBUG: Thread BackgroundLoader 2676839280 terminating
2019-04-11 19:29:11.247 T:2876646256 ERROR: CCurlFile::FillBuffer - Failed: SSL peer certificate or SSH remote key was not OK(60)
Sounds like an AVR problem (maybe too slow for 4K). Change the cabling that way:
- video: RPi -> TV (regular HDMI port)
- audio: TV (eARC HDMI port) -> AVR
eARC is made for audio transmission, so I think CEC signals are left out by design.
LE's CEC client works out-of-the-box. Make sure you have been activated CEC on your TV (External Device Manager, option Anynet+). Also check your HDMI cables, as described at your 4K thread.
Do you use 4K HDMI cables (HDMI 2.0 or 2.1 standard)? If not, then low HDMI speed can lead to a limited whitelist of HDMI modes.
Can you copy the kodi.log from microSD to your PC? If yes, upload it to Pastebin and post the link.
I am using a MariaDB docker to keep a centralized database on my Unraid servers SSD Cache Drive.
I think it's a DB issue:
2021-01-07 18:36:09.664 T:1675469696 DEBUG: RunQuery took 22 ms for 106 items query: select * from episode_view WHERE (episode_view.idShow = 223) AND (((episode_view.playCount IS NULL OR episode_view.playCount < 1)))
2021-01-07 18:36:09.665 T:1675469696 DEBUG: DatabaseUtils::GetSortFieldList: unknown field 31Try a different MariaDB version on LE.
Disable WiFi and Bluetooth for testing.