Enemy Wave Spawn System Assistance

Hello, I am currently working on a simple rolling ball game where the player has to stay on the single platform while enemy balls try to knock them off. I am expanding on the concept that I found in Unity Learn Tutorial 4. The spawner at the moment works but only 1 enemy spawns during each wave, so their is no sense of challenge. I researched various different spawn systems, but so far I have not been able to get the results I want.

I also have a UI system set up to announce when a wave starts and to give the player a moment before the enemies actually start going after the player. The system is also supposed to say when the wave is over when the last enemy is defeated, but the text never shows up.

One of the bonuses that I tried implementing from the tutorial stopped working appropriately. I had a boss enemy that would spawn in after a certain number of waves, and it would also spawn enemies but now the mini enemies do not spawn in.

I know it's a lot to go over, but I was trying to flesh out the concept and make it into my own game.

If anyone is familiar with designing a system like this please let me know any assistance is appreciated. I can spawn the code I have at the moment later on if that would provide insight into the problem and to come up with a solution.

Link to Unity Tutorial: https://learn.unity.com/project/unit-4-gameplay-mechanics?missionId=5f7648a4edbc2a5578eb67df&pathwayId=5f7e17e1edbc2a5ec21a20af&contentId=5f7649a0edbc2a2315d471f7