Ok, so Elite Guard 5 just ended and I managed to get to top 500 in ranking. I was able to do this by saving up items from previous events. Not to mention I'm lv62 with 800+ SED. I really don't spend any money on this game beside one per day e gacha tickets for $1. Soooooooooooooo, do you guys think it's possible or Nah?

Certainly, there are people here who do that

When I try, I can rank high enough in every event. I can even complete Gambit collection to 50k. All for free.
However, for me it simply isn't worth the time investment. But it can be done.
I don't even bother with gambit any more, but EG is still very easy to get high ranking even with barely trying.

I newer spend anything money on PeroPero and got to top 250.
F2P can get most girls if they are very active.

I agree. I'm very active myself so I end up doing well anyway.

I'm F2P and got top 500, top 500 in support, and over 200 SEGs. I've not even been playing THAT long. Still have about as many half puddings as I had when I started, though I burned a lot of full puddings.