Module milestone??

I haven't paid much attention to the non essential modules much but today I got curious and started merging them up. To my surprise now they are all Mythic+ at least, meaning that I only need copies of themselves to upgrade the remainder to Ancestral and add stars.

So now I can safely shatter any additional rares I get and only keep epics I get, right? (Unless I eventually want to dupe some) It shouldn't be too many gems to unmerge what I accidentally over-merged.

Should I hold off shattering until I unlock and start researching Shatter Shards labs?