Just out of curiousity, what would happen if you placed a male betta fish with 5+ females?

I have done this, one of the females was actually the alpha and picked on the male a bit even!

They lived fairly peacefully for 5 years. No mating. Heavily planted tank.

The aggression was spread, and I did have guppies in there with them to help.

It does depend on the individual fish.

If you plant to try, be sure to introduce all at once, have it HEAVILY planted, properly cycled, and tanks ready if you need to separate them.

You may be able to keep a group of females peacefully. But adding a male will create competition and they would be in constant conflict on all sides. He can only raise one brood at a time, the females would fight for access to him. He would also likely attack any timid or non-breeding females, and dominant females may attack him.