Have a lot of slow ships? Consider unlocking Zenith Spacetime Manipulators. I believe you can find ZStM under support, and unlocking them costs 1750 knowledge. You can build up to 20 of them, but each requires 20,000 power. They boost speed by 20, stack with each other, system ownership, and logistics command stations. While they can move, they unfortunately cannot travel through wormholes.
Examples:
Zenith Viral Shredders (52)
Plasma Siege Starship (36)
Zenith Bombard (44)
Armored Golem (44)
Artillery Golem (32)
Spire Mini Rams (56) the full-sized asteroid version is immune to speed boosts
Fallen Spire campaign ships (56)
With just the system ownership speed doubling, Zenith Viral Shredders can have trouble reaching anything that isn't nailed down by tractors. Throw in just one or two ZStM and you'll spend a lot less time closing the gap on ships trying to threaten your frontier planets. And since Zenith Viral Shredders reproduce slower when you have too many on one planet, your ZStM network will make it easier to spread them out among all your planets and still pull everything back in a hurry without the hassle of transports, if you're in danger of being overwhelmed.
If you feel like going overboard in one system, rather than spreading out the benefit, you can easily get Plasma Siege Starships to 300-400 speed. How's it feel to be kiting Hybrid Hives with your slowest ship? Be sure to turn on auto-kiting for maximum fun.
If you only have one chokepoint, ZStM are a little lackluster, since you can nail everything down with gravity and tractor turrets. If your galaxy map/settings makes Warp Gate raiding prohibitive, such as a crosshatch or cluster map, then ZStM can make defending your borders so much easier. Transports are still, of course, the fastest option for getting around, but your fleetships will be so much more responsive wiping out incursions and FRD will be so much more effective once ships chase stragglers less and get back into position that much quicker.
If you have that distributed front line and cannot afford to plop down logistics everywhere (military, economic, warp jammer command stations), then you'll also have a much more fun time kiting threats with missile frigates and riot starships (lasers, of course). You'll waste less time fighting inferior forces, chase down starships bypassing your turret balls, and other fun.
While you can build them into a beachhead, the sad fact that you cannot take them with you means this isn't a game-winner. But if you have either melee units, exceptionally slow units, or particularly long ranged units, or even just moderately slow and longranged units like missile frigates and anti-armor, the sheer rush of outmaneuvering attackers is hard to beat. That is, if you don't kill everything directly on the wormhole or FRD everything anyways.