First of all I'd recommend updating to LE 9.2 - 8.2.5 is quite old.
To change the protocol simply use ir-keytable -p ... (leaving out the -d device) or specify the rcX device with -s rcX.
Your IR receiver is a bit limited as it contains a hardware decoder that only supports a few protocols. It should work fine with the remote that came with it but it- could well be the remotes you tried use a protocol that this receiver can't understand.
For further info also check the Wiki: Infrared Remotes [LibreELEC.wiki]
so long,
Hias