Snake game slows down as new body squares are added

Hello! So I implemented a few new changes to my snake game and now it’s capable of automatically adding new body squares when the green square is picked up. Unfortunately it appears that the snake slows down as new body squares are added and I was seeing if I could receive help on why this is occuring. Also apparently someone else ran the game on their computer and it almost crashed their computer when they got the snake to a length of 9, but the game runs perfectly fine on my computer besides the snake slowing down. I was seeing if someone can test the game and help me out. This is also a personal project btw. Thank you! https://codepen.io/bbg4/pen/xxeBVOZ?editors=1010