Help me to cast more than one spell per turn

I would like my Pantlaza deck to play a little smoother, as I have repeatedly encountered the problem of only being able to play one big dinosaur spell despite good early ramp, and then having to pass with 3 open Mana and no further options. This meant I couldn't keep up with the other players.

Playing Pantlaza in round 3 isn't really my primary goal (currently, I could only do this with Sol Ring or Abundant Growth in my starting hand), because the tempo in my group isn't really worth it and Pantlaza gets shot right away.

The problem is made worse by the fact that once Pantlaza is destroyed, it costs 7 mana and I usually can't play a second spell that turn.

Does anyone have any ideas on what I could do better so that I can take more actions in the game?

Here is my deck list: https://archidekt.com/decks/14278039/pantlaza_sun_favored_upgraded

I recently removed the sideboard cards to fix the problem, and the cards in the Maybeboard are still lying around here.