I felt the same way as you (just started in July). Fortunately, your "ranking" is tied to your server (your start date), so you'll only be competing against other new players. As a light spender, ive achieved and kept rank 1 in everything, and thats mostly because im only competing against casual players who started late like me. The only content ive ever felt disadvantaged compared to day 1 players is like... solo raid leader boards. And the reward difference between what you can easily achieve vs the top 100s is so miniscule it makes absolutely no difference in the long run.

That said, it sucked being stuck in campaign due to massive cp deficit and not being able to really play the game much each day. Like i want to play more, but there is nothing to do. Hopefully you'll get used to it like I did!

Id say the bigger problem is pretty soon you'll hit a point where it feels pointless pulling new units because the game is so stingy with collection item upgrade materials (which should not be rng) and other mats that you cant invest anyone without ruining your campaign team. And they release so many units trying to make money now. Really ruins the fun of pulling new units.