Is it possible to disprove or refute the seemingly indubitable Cogito ergo sum?

Is it possible to disprove or refute the seemingly indubitable Cogito ergo sum? Is it possible for even that to be doubted? Is it possible for something to think, but it does not exist? In my opinion, I think that the only "thing" of which anything that "thinks" could be certain, is that, "there is something," "it is," "there is," or "it is." I feel that for one even to doubt that "there is something," there has to be "something," or one could not doubt at all, or that there could not even have been a "one" in the first place to do anything let alone "doubt." I have just confused myself now, and I apologize for not explaining this much better. I am trying to go beyond René Descartes, and "truly" find "something" that could not be doubted at all, or is it possible to doubt anything or everything, even that statement itself, ad infinitum, and even that?

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