Welcome back! And thanks for the kind words.
What you are noticing isn't a visual speed thing, it's actually the simulation speed of the game. Previously, the game defaulted to a slower speed setting, but due to overwhelming player preference for the middle-speed, now it's the default. But the old speed is there! It's in the lobby, and it's called Epic. What used to be called "fast and dangerous" is now Normal, and that's what is throwing you off, I think. There's also a new Blitz speed that wouldn't have been there when you were last looking at it.
What you've been adjusting with the +/- keys is literally the actual framerate of the game -- which does slow things down, true, but it's like running in slow-mo (hence the jerkiness) rather than having your and enemy ships simply move at a more sedate pace. You're definitely not the only one who prefers the Epic speed, so no worries! I think it's actually labeled Combat Style in the lobby.