I think you're right about the beginner bot. The bots are currently arranged by how long they play for on average and how likely they are to win. Which isn't super noticeable when playing them. Based on all the feedback, I already have a potential solution I've already partially tested a bit.
Easier bots will play slower on average, this makes it a lot more fair. I'll also make sure they are guaranteed to win so you don't get free victories if you're not fast enough. And lastly, I'll make sure each difficulty has a minimum amount of steps so that the bots don't randomly get a super lucky game. Master difficulty will be pretty much the same.
Thank you for your feedback and kind words!