Self Publishing Conundrum

I have a question for those who have already dipped their toes in the world of ebook self publishing on Amazon and other venues.

I have novels in the works, none yet finished, but hopefully soon. Before I put those out when finished, I wanted to already have a presence on Amazon, so what I thought of doing was releasing one or more anthologized collections of my short stories. Here's the catch, while I tend to write in SFF I also write occasional mainstream style stories. I would like each/the anthology to be at least novella length, but the only way to achieve that at present is to use all my best stories in one volume. That mean's mixing Easter themed mainstream with "digitalized" humans in outer space science fiction, to Prachetesque fantasy satire. Those are not the same reader markets, and each responds to different cover designs and story types. If I keep each anthology/collection to genre, then each is going to struggle to reach 17,000 words, (average story length about 8000 to 9000 words.) This is not a problem in itself, but if I place each genre collection on Amazon, I'm going to have to charge at least 99 cents. There are whole series collections on sale for 99 cents. So in that light it doesn't seem like it's a fair price for the reader. They should get at least a novella length for for 99 cents, I think.

Yet I wonder if I hurt myself to bundle it all together with each genre in it's own section. It feels like I would be attempting a ham banana sandwich at a sushi convention.

So, should I publish each genre collection separately and just choke on my reluctance to charge 99 cents; bundle several mixed genre stories together, and hope readers are open to new and different things? Or something else? Thanks.

short addendum: I'm aware of the "solution" write more stories.

Thank you all. My SFF stories do tie into the universe(s) developed in my longer works. My few mainstream stories are the outliers. I did not expect a few short stories from an unknown to make a big splash, but I did hope they might generate enough to pay for a website, and once I have other offerings, they could become sampler fare.

I also look at self publishing smaller works as a learning tool to make sure I know what I'm doing in terms of publication formatting and cover design. It's my toe in the water, start a mailing list, figure the world out in safe mode before I launch anything bigger.

Theres a thought. I'll have to think about that price point. My stories do range a bit in size and subject: Russian monks building a city on Mars, Brain damaged kids who get lost at church on Easter, A man who sells glimpses of a child's future in a wad of pricy chewing gum, A trash picker who cleans up lives, Mineralized human neurosystems encased in psychoactive polymer in space ships the size of soda cans swinging for the nearest star, nerdy kids who kill their snooty rivals in dance offs with mutant chickens, aging superheroes and super villains escaping the rest home for one last fling.

Several good points to consider. I do plan to go kdp select, don't know anything about scout. KDP Select is part of the reason I thought some shorts might work. Readers are not so "attached" to the price or length of a given work, or the celebrity of the author, but mostly by whether they enjoyed what they read. As an author I would be paid according to percent of pages read, and in a KDP environment, I'm guessing, perhaps wrongly, that this would be a steadier income stream than straight selling as an unknown.