Some device developers do add support by the manufacturer, these can then be adopted by LineageOS and made official or continue to be supported by a third party (or be discontinued)
Please correct if wrong, but most chats/forums/communities condemn/remove any device support request.
I may see if I can find one but, it would be significantly better if Purism could contact them, being the manufacturer.
I would also like to note that although I might not have the technical experience, if someone does and is willing to donate their time in order to support LineageOS it would be greatly appreciated.
Cheers,
@TheMountainSquirrel 