Hal 9000 said:
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 thought the Final Order fleet may have been built also in Outer Rim and/or Unknown Territories (maybe some built on the Exegol planet too?) over many years and then it grouped together or ‘parked’ at Exegol waiting as the ‘right time’ came closer.
The Final Order fleet would have done battle drills or training during the time waiting to practise too? Out of sight of course.
This is just my understanding from the film, I may be remembering wrong, and some lines of dialog were difficult to hear.
I think Kylo wanted the power of the Final Order fleet to join his forces - become more powerful, to make his rule easier. A trick by Palpatine to get what he wanted.