Well, that was just a Klingon task force, not the entire Starfleet! Here’s where the writers play fast and loose with numbers again, which many have already pointed out with “entire” fleet. What we saw on screen couldn’t be the “entire” fleet of thousands of ships. From that density on screen, I could only imagine hundreds of ships, not thousands as implied during Dominion War. If they do go by hundreds, then we are back to 23rd century Kirk-era Starfleet which also doesn’t make sense.