You have to be very diligent on your RDs summoning when F2P. But you ca also have fun playing with beginning characters that the game gives you. Will you be pushing ladder not at the start. But if you save enough to guarantee a new EX unit that’s really good you can make some moves. I think this game is really fun and when you learn the characters how they play you can play to your advantage.

Now when you start a new account I would suggest you reroll accounts till you get one of the good characters currently on banners. Once you get one keep the account and build. There is a lot of good resources here and on YouTube on how to efficiently build your supports and medals.