Yes, there are a quite a few issues. I think it is better to start from scratch as it'll be hard to unpick all of the mistakes.
Here's what is wrong though:
1 - DT_HELMET_Official
You've edited the bindings wrong, you should only have changed the last part as I said, it should look like this:
View attachment 793736
Also it seems you have edited the ID used for Oettl? (114 in base game but 118 in your screenshot)
That is not necessary for this change and will only cause complications.
2 - Incorrect customization data file has been edited
I can see what you've tried to do here, make the file that is pointed to in the bindings file. Nothing wrong with doing that in principle but again is more complicated than is necessary.
The file you actually want to edit is "helmet065_114"
Replace all instances of 065 for 042,
except the material instance lines:
Also remove the _nospoiler parts.
View attachment 793740
That will do the trick.
However, HJC helmets are actually unique, the way their customization data files are structured are different because the helmet mesh is named differently. You can actually skip the DT_HELMET_Official change for this type of helmet.
If skipping that step then helmet065_114 would be edited like this (lines 1 and 11 are left as 065):
View attachment 793741