Change your NetworkingMode to Predictive and not Auto. It'll help avoid some issues botting if you're client is using lockstep, but if it's using predictive already, you won't notice a difference.
Frame time is affected by code the bot runs in a single frame. The more objects and effects on screen, the higher the normal client frame time is, and then the added effect of the bot having to process those objects is what leads to frame time spikes.
A large part of the performance impact of running the bot comes from using OldRoutine and running combat logic. If you were to run a simple follow bot, for example, you'll notice there's hardly any performance difference. This is because the bot isn't having to process a bunch of complex objects in game memory, which requires accessing a lot of underlying data to figure out what it can attack or can't. This adds up really fast and you start to see the frame overhead as it's a lot of CPU and memory reading going on.
This is just a limitation of how an external bot that has to sync with the client works. There's no way to not affect frame time and have EB work the way it does. The only way to really improve performance is to have the bot do less, not process objects as much, and things like that which create undesirable side effects.
