Unfortunately, my Discord isn't working. I mean, I have Meridian Goldshards installed in the eye, heart, and core slots. All three. However, all three best methods remain locked, indicating that the last requirement—the one with the Meridian Goldshard—isn't met.
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You need to pick only one to install big shard, all others must be installed with small ones. And each of three methods gives different stats of outcome, depends where you put the big shard, so pick one method you prefer, and install goldshard where it says. Also using all 3 slots with big shards did nothing special, you sill get same reward as if choosing only 1 of them, so no difference here after updates.