That pretty much sums up why I gave up playing with Real Stars: Nothing to fight, no habitable worlds, long stretches of boredom.
Oddly enough, I'm having the opposite problem. My Real Stars campaign (on hiatus) had a fair number of habitable worlds (2 completely habitable ones right off the bat, a few more under x2 colony cost, and a TON of x2 colony cost worlds), and 3 NPRs (not counting a robust Precursor presence and the Swarm).
My current nebula-start game has found a ton of nitrogen-oxygen worlds, but every single one of them is uninhabited. I finally got a hyper-scout built to go check out two binary systems where the companion is thousands of AUs out with no L-points. Even those were uninhabited. And minerals seem to be much scarcer than in a Real Stars game (could be the prominent lack of old M-class stars?). I've run into a couple of Precursor packs and there's at least two Swarm queens out there. But no NPRs.
I think you are right about the cause being the lack of old M-class stars. I imagine the real reason that you're not finding much minerals is because you are in a nebula. Nebulas generally only have small planets, tiny moons, and the occasional asteroid belt. Remember that nebulas are infant systems: the whole reason the nebula exists is because many of the particles (and thus minerals) are part of the nebula cloud itself, and thus unavailable to be harvested.
Also luck.
For NPRs, I've suggest "create system", then "create NPR empire" on a nice planet. You'll always know about the system, but never know how the NPR is doing or when your main empire will find the system you created.
For fun, I created a "real stars" game where I deleted my starting Earth population, created an NPR empire on Earth, then created a new human empire in another system I created. I'm still waiting to "reunite" with my Earth relatives. I also gave my new empire lots of genetic low temperature techs, and I learned a fundamental lesson about genetics: it sucks. After spending most of my starting points on genetics, I still can only create a race humans with a minimum temperature of -40 degrees Celcius. Only another 200 degrees until they can live on an absolute zero world...