Doing a 510k w.o that experience/perspective seems insane (especially for a startup(?)).
Also, I'm not sure which field you are in, but I've generally been able to access the applications from previous submissions in my field (Personal exoskeletons).
For our product category (sleep apnea diagnosis) the FDA has an unwritten rule that all devices must run a clinical study compared to existing tools.
The hard part has been extracting the exact details that would make an acceptable study in their eyes (testing environments, statistical methods...)
Also it seems like the testing standards have evolved over time and this isn't documented either. Only way we've been able to learn the standards is by giving the FDA a proposal and getting feedback on it.
We've gotten a few FOIA'ed 510ks of similar devices. Unfortunately they are 90% redacted and not very helpful.
Looking back on it, it may have been worth it to seek out a person who had gone through this exact experience before. That could have saved some time/effort.
What they did provide was a means to package our paperwork together in a way that is recognizable to FDA reviewers, and the resulting work is what you see in the StartupFDA repo.
We still had to produce all the work, and interpret the FDA guidelines on our own. It was a bit of a compromise on speed and cost, but worked for us.