Have you heard of the new handwavium/unobtainium alloy? It's unbelievable stuff if you can get some.
Boo. Hiss yourself.
Here's a tentative timeline/slash TL Chart for Gravitic Technology
TL 8 Lifter technology. One to six diameters distance. Note lifters will take a looooong time to actually get you to orbital velocity but you could always use them to loft a ship and start her rockets further up in the gravity well for a savings in fuel or use the lifters to compensate for planetary gravity allowing all your thrust to accelerate a ship.
TL 9 Maneuver drives (whether reactionless ar super efficient rockets depending on YTU. Around this time a heat dissipater is invented from gravitic making heat radiators unnecessary.
Late TL 9 Jump Drive possible
TL 10 Jump Drive discovered through heat dissipater research.
The heat dissipater is my way of hedging my bets. Which is another way of saying I'm answering the questions no one wants to ask. It evolved when engineers designing air/rafts discovered they ran a lot cooler than the math would indicate.
Eventually engineers found a way to maximize the heat loss while the scientists where still scratching their foreheads about where the heat was going. A lot of different proposals (stored in the quantum field, neutrino emission, energy matter conversion on a minute scale) are made but some scientists are thinking out of the box. Engineers don't wait for them to figure it out, they trash the heat radiator industry and build stealth capable spacecraft.
At TL 9 lifters can be made far more efficient in terms of range and heat build up by fine tuning the system, leading to the maneuver drive and more extreme gravity effects being possible.
By TL 10 most cultures figure out where the heat energy is going: to jump space. The repulsive power of antigravity opens a micro wormhole. That's where the heat goes and also other energy. enough power in a specially constructed drive will open a wormhole into jump space and make FTL flight possible.
As an added bonus scientists figure out information lost in a black hole's singularity winds up in jump space and apparently an infinite number of mismatched socks, hotel key cards and fabric softener sheets.