I'm new! Want tips and advices :)

Hi guys! I'm very new to this game, I'm playing literally for only two weeks now.

I saw some things on here already, like how to play claw machine balance thingy and that the galaxies coordinates are basically random. So if you can give literally ANY tips or advices about the gameplay, banners or any other things i would really appreciate that!

If it matters, currently i'm on 44 hunter level, i opened all the LI but chronologically i just completed Under deepspace 6. I didn't opened Unicorn operations and Abyssal chaos yet and i guess everything else is open for me.

I guess i'm f2p mostly, cause i don't wanna spend a lot of money on the game. So from the gameplay i already had, i understood that the point is basically to alternate between grinding for affinity levels, stamina/hp/gems ect. and actual gameplay with levels and banners and that's it🤷🏻‍♀️

I also have a few specific questions. As far as i understood majority of 5 star memories are limited and possible to get only through banners with ?golden tickets (idk how do you call them) and boxes things. So the question - is (was) there an option to get some of the previous limited 5 star memories? Like, maybe there was an occurrence when there was released some limited banners that were repeating some of the most popular memories, idk? And also in the shop, in wishing well, all the 5 star memories have "rotation" mark/label on them. I have no idea what that means honestly. So if you can give me more information about the 5 star memories it would be really great.

Also I didn't fully understand protocores yet. I can get them from core hunt, i can apply them to memories, update them. But what they actually do in the battle mode? I don't understand what they provide and would it severely affect battle performance if i don't use any protocores?