json_attributes: >-

[viscid valve]

I know this is not template, have you tried jq ?

So the answer seems to be 'no' I guess, not for the fainthearted but check this https://www.baeldung.com/linux/jq-command-json

The idea (not sure if that fits), is that you rework the json in such a way that it provides a formatted json that you can then load as a single attribute, alike forecast in weather sensors