Firstly and fore mostly, I am so sorry that you feel this way. Games should feel fun and I apologise for any stress of frustration this game has caused.
I was quite surprised when I read your post when you mentioned how the game works. I think it is really interesting to see how sometimes RNG can mess with us. Truth is, there is really nothing under the hood. The value of your island displayed in the stats is simply for aesthetic purposes and it really does not affect the enemy generation. It is the same thing for item drops. Item drops don't have access to view your island and determine if you need a certain item or not.
The one thing that exists to try and minimise the RNG in the game are the forge and shop, though the forge does a poor job of it right now and feels very random. The shop will always contain certain types of items so that if you are lacking in a certain item like floatrons or shields, you can fully rely that the shop will have them.
That being said, I have future plans to make the player feel less frustrated, since I am certain you are not the only player who feels this way. One thing that significantly hurts the game in terms of replay-ability is the lack of persistence between runs. I have plans in the next few months to add this basic feature and was actually gonna have some sort of permanence in the next big update. However there were some core changes that needed to be made that will significantly affect the game in the long term, so I have delayed it until those changes are complete, but it is still scheduled for being up next.
Thank you so much for sharing your feedback again!