Lord Ganesha, Goddess Saraswati, Goddess Durga.... Lord Narayana, Lord Narasimha, Lord Vasudeva, Lord Varaha, Lord Lakshmana.... are the angas of Lord Rama.
So Lord Ram is definitely not from Narayana or Vasudeva, both of which are commonly considered Vishnu, but other way around. Now as per Krishna Upanishad, Lord Ram said:
When I reincarnate as Lord Krishna, you will be born as Gopis
Doesn't Krishanji in BG Ch. 10 says he is Vishnu only among Adityas? Now as per Ram Tapaniya Upanishad:
The word ‘Rama’... indicates Para Brahman itself.
The body has been ascribed to Para Brahman... the entire world exists in the seed “Rama”
‘O Rama, you are the supreme being, of the nature of Sat, Chid and Ananda.
I don't think any Upanishad has called Vishnu Satchitanand. And Narayana Upanishad says Vishnu was born from Narayana:
nā̱rā̱ya̱ṇāddvādaśādityā rudrā vasavassarvāṇi ca cha̍ndāg̱ṃsi | From Narayana, the twelve Adityas, eleven Rudras, Eight Vasus and all those meters (for writing) were born.
The twelve Adithyas are... Vishnu
Narayana (anga of Ramji) also seems somewhat equated with Vishnu here. So it Ramji an avatar of Vishnu as per any Upanishads? This could be from 108 Muktika Canon, Shaiv or Shaakt Upanishads... or even others like Allah Upanishad?
Or is it clear Vishnu is only one part of Lord Ram?