A high number of tokens makes your server very slow
My opponent has a Soul Warden + Horn of Gondor combo, and I have Platinum Angel which prevents me from losing.
The problem is that whenever my opponent activates Horn of Gondor or attacks with all his creatures, the game becomes very slow.
I don't know how your code looks internally, but I suspect you do something like creating a new object for each creature on the battlefield, which in this case is not optimal. You could optimize your code by instead only creating one object per unique creature, and storing the number of such creatures as an integer. You could also do this for elements on the stack for things like Soul Warden.
That way when a player has an infinite combo like this all that happens is ones are stored in memory instead of zeros at certain positions, which shouldn't make anything slower. I don't know the details of how your code looks at the moment, but you're obviously doing something that's not optimal since it's way slower than it should be.