Looking for some BUILDERS to teach / guide me

A duplicate won’t be tolerated, so maybe rename roomservice.xml to roomservice_xml

so that, late edit, the “old” roomservice_xml goes “unreadable”
and the “new” <device>.xml is acted upon.

Worth an explanation … is a good plan when building an unsupported device – you will have wanted to do good preparation.

A Lineage supported device provides roomservice.xml, but that will require the addition of extracting blobs or an additional project that is the vendor source from perhaps Gitlab or Github, as you just did in the post above.