It seems your questions fit in well with the so-called Samyukta/Samyutta Buddhism (SA/SN) in Early Buddhism (cf.: The Samyutta Nikaya as the earliest of the EBTs - Discussion - Discuss & Discover, and are not anachronistic interpretation (“Earliness” of Pali Suttas vs Chinese Agamas - Discussion - Discuss & Discover).
This is because the SA/SN textual collections contain both
(1) the core teachings of the Buddha (cf.: The sūtra-mātṛkā (sūtra matrix, 契經, 摩呾理迦 or 本母) - Discussion - Discuss & Discover), and
(2) faiths in the sense of general religious beliefs on spiritual/divine beings (devas) (cf.: The sūtra-mātṛkā (sūtra matrix, 契經, 摩呾理迦 or 本母) - Discussion - Discuss & Discover
In this connection, Samyukta/Samyutta Buddhism (in Early Buddhism) was a system for both
the fundamental teachings of Early Buddhism, and
early Buddhist adaptation of general Indian religious beliefs about divine beings (devas).
“And most importantly - does it matter?”
Yes, the system recorded in the earliest Buddhist texts (SA/SN) is certainly essential for us to understand Buddhism from Early Buddhism and beyond.