I haven’t heard this come up, but if the Sith could muster “the largest fleet the galaxy has ever known” with full compliment seemingly from the resources of their own little planet, then why didn’t they do that pre-TPM? Why did the Sith need to carefully infiltrate the existing government and pull strings to secure an army? Couldn’t they have just taken over the galaxy by military force as TLJ implies the First Order was in the process of doing before Palpatine appeared and declared the First Order basically pointless?
I was confused about this as well. According to the visual dictionary for TROS, the Sith fleet was manufactured by Kuat shipyards. Apparently some of the Sith cultists worked at Kuat engineering and smuggled parts to Exegol. This kinda makes sense, though I don’t get why the fleet can’t navigate from Exegol despite all these ships going back and forth for 35 years, delivering parts.