Yes, rebuttals by a bunch of philosophers who, like you, can’t even accept their own existence or get hung up on the definition of “I” and “think”. “I” doesn’t need to be one’s physical body as one perceives it. “I” could be a brain in a jar or a computer generating an entire simulated universe or a bored deity. But something that you are, or at least I am, is producing thought about itself and its input stimuli.
Anyone who can’t even accept the fact that, by thinking, they must exist in some capacity in order to be capable of thinking, is being obstinate for obstinance’s sake. That isn’t a philosophical question. It’s refusing the answer provided by your own experience in order to be the most pedantic person in the room. So, basically 20th-21st century philosophy.
Or maybe you really aren’t sentient and I’m wasting my time with an NPC.