When I bought my 2021 Isata 5 30FW in March 2020, when we were closing the financial aspects, the dealer showed me two documents he was filing on my behalf. One was the warranty start with RAM and the other was the warranty with Dynamax. Definitely get back to your dealers administrative staff and find out why this was not done.
I asked my RAM dealer what my warranty start was when I had my first oil change and they told me March 2020.
2021 Isata 5 30FW
2014 Honda CR-V