how to get grek module Ⅰ

I want to get grek module Ⅰ and MkⅠ basic performance core.

I recently returned to the game during Zeb's Marquee event. Because of this, I missed out on the initial resources needed to upgrade R5D4. I accidentally ended up using the resources on GroguAnzellans instead, and now I'm completely stuck with no other way to obtain them.

The Era Store only shows "Greeg Modules" tier 5 and above, so I can't get the lower-tier materials anymore. Do players who join late or miss the early phases not get enough materials for all the characters?

I am completely willing to spend real money/pay to get them. Any advice would be highly appreciated!