Moved to own topic as nothing to do with TTN v3 & LG308.
Please read THIS post on how to format posts.
The decoder will decode but it seems you are trying to find a way to get the data out of TTN and on to somewhere the data can be displayed.
In that instance, Integrations are where you need to look:
https://www.thethingsnetwork.org/docs/applications/index.html
Please bear in mind that, a, v2 will close by year end and b, there is no myDevices in v3 and we don’t know when or if there will be.