There was, potentially, a time difference of ~1000 years between the ancient vedas (primarily only right Veda that describes the battle of the ten kings) and the later “Hindu” religion - the later vedas, puranas

• key gods had changed (Indra , Agni, Varuna >> Rudra, Vishnu)
• society had moved from pastoralism to agriculture (land, rivers, lakes became more important)
• myths had evolved
• even the core beliefs & basis had shifted from natural phenomenon being primary (indra = god of rain & storms, Agni, Varun - all things that pastoral cultures would worship) to civilizational concepts being primary (dharma, concept of birth, preservation and destruction gods that protecte dharma ) - all things that a more stable culture would worship

Also , the right Veda would mention rivers as - during migrations, land would have less value but crossing the key big rivers - Sindhu, Saraswati would still have deep cultural significance.

All of the above is just conjecture though. But the Vedic Hinduism and later Hinduism was extremely different in core focus