As f2p it is important to spend your resources wisely. It takes 15x SSR awakening stones to max awaken one piece of SSR gear so be careful what you spend it on.

You want to comfortably get to a stage to farm PVE reliably which are Red Demon, Grey Demon, Books, Boss Extreme stages. To get the maximum value you should upgrade these gears (see image above)

Focus on raising DPS units!

Not only is this setup better CP value than having the whole left side SSR and the right side C it is the same amount of resources and gives you better clearing power

IMPORTANT

Your power curve is slightly slower when using the SSR ring instead of using the maxed C version for the quick 13-15% atk boost but the base atk is also way lower on the ring itself but once u put a few resources in it should even out soon enough.

ALTERNATIVE

Use a maxed C ring for temporary boost but it is important to not waste resources on a left side SSR DEF amulet.