yup what he said, you could use a dynamic mike the heil pr20 has a version for video cameras and in terms of quality is far above what most will use, but the true test of quality is technique, the mic can only give what it hears, so if you are in a noisy reverberant room, you are recording noisy reverberant audio no matter if the mic is cheap or expensive.
Assuming you have 10k in cash, I would recommend any of the other recommended cameras, but renting camera and lens for your projects. Buying a camera in the 10k range has rapid depreciation and unless your workload justifies the payments is a big money loser for you. There are many used cameras and used lenses that will give you excellent output given that you have the skills, inspiration and experience to benefit. The camera is not the arbitrator for quality, your ability is. Renting a camera and lens when the project justifies it is how many pros roll
I think the crutch of this discussion is, "does quality result from purchasing expensive camera and glass or is quality a function of using a camera expensive or inexpensive skillfully?
What matters more, expensive camera and lens or good lighting?
or camera setup regardless of cost
or good composition
or great audio
can purchasing more expensive equipment substitute for skill, talent, inspiration?
In my heart of hearts, I believe that I can take a cell phone and make a good movie, it may be inconvientant, but accomplish it with skill, talent and inspiration and so can anyone who studies, practices movie making, choice of camera makes no difference, if the camera or more likely the lens has flaws, then it the good cameraman will use it as a special interest lens or give their film a unique look.
If it is truly guerilla fllmaking then use a cell phone, you wont be noticed.
get this book https://www.thriftbooks.com/w/dslr-cinema-crafting-the-film-look-with-vi... by kurt lancaster called dslr cinema. Ignore the camera recommendations, but absorb the basic cinematography. Then look on youtube for all the 10 min film school videos by director robert rodrequez. I also recommend the book making video that doesn't suck. Get a monopod for stabilization even before a tripod and then make 20-5min film, script them if you can, but even the days when you have no idea what to shoot, go outside and shoot or if you have no idea what to shoot, then shoot a 5 min film on I have nothing to shoot about today. Use your lack of money, skill, actors and all the reasons that prevent you from filming, just move beyond that, shooting 20-5 min films will teach you more than any book or article and learn to read your films for quality, look at the first and last film and take notice of the differences, have other filmmaker critique your films, not because they are right, but to give you a technical reaction and feedback, trying some things that don't work and fail and you may discover something new.