Has anyone been able to succesfully debunk a breadtuber besides the althype? Althype really needs to debate them.
Yes, many people from very different perspectives actually. Just to name a few:
Rubble of Empires: Communist YouTuber who thinks that postmodernism and wokeism was invented by the CIA. Shits mostly on troons and how they use questionable data (for example intersex people) to justify their lunacy. He also used race as a reference, since it's a uncomfortable analogy for progressives: "When gender is a social construct and a bearded man can call himself a woman, why can't a white person say he's black and you have to believe him?" Progressives' answer to this are just hilarious, since they can't answer this question. Race is much more a social construct than sex/gender, since it isn't as set in stone, and is strongly influenced by genetics, geographics, religion, language and customs (hence Greeks are considered White, Lebanese not. They're genetically very similiar, but the fact that Greece is in Europe and Lebanon in the Middle East, Greeks are mostly Christian, Lebanese mostly Muslim, Greeks speak a Indo-European language and Lebanese people mostly speak Lebanese Arabic puts them into different racial categories in the Anglosphere). So it makes absoutely no sense that a biological male can call himself a woman, whereas when a white man says he's a black man it's haram (There are more genetic differences between a man and a woman from the same race, than genetic differences between a man and a man from a different ethnic background)
Contra's troon sidekick Riley Roshong actually watched one of his videos and thought that he can easily debunk Rubble of Empires. What happened? Riley Long-Shlong was constantly contradicting himself and wasn't able to attack Rubble substantially. Just think about this. This wasn't a debate, but a debunking video and Riley wasn't even able to properly strawman him. He also makes some short compilation videos in which for example biology and troon expert Xanderhal asks unironically "Wait, what is a gonad?".
The Distributist: Tradcath reactionary. He's fairly intelligent and well-spoken and (I think) genuinely a nice person.
Quite different from most other tradcath YouTubers. Some years ago he had a debate with pre-troon Contra. Nyk was even worse in this debate than in his debate with Blaire White, and this says something. He made many videos talking about BreadTube and the progressive left's inconsistencies and also had some debates with known figures like CuckPhilosophy and BadMouseProduction (in both of which the Distributist had the upper hand).
King Critical: A male TERF who actually started with the view that gender is a social construct (some leftists accused him of lying. He showed then several screenshots from some years ago how he actually commented on Contra's videos and how he talked shit about TERFs). He then engaged with TERFs and was actually convinced by them. In one series of videos he deconstructed the video of Contrapoints called "TERF" and showed that Nyk tried to convince his audience that "Terfs are evil" by using emotional manipulation, ad hominems and logical fallacies. He mostly focuses on troon issues, but talks about other stuff as well. He isn't right wing though, so he's probably much closer to BreadTube than any other person I've mentioned here. This, however, makes his critique of troonerism stronger in my opinion, since he's attacking his "own side".
Rod Fleming: Not really involved with debunking BreadTube, but he once made a video about ContraPoints. He's a sex researcher and firmly agrees with Blanchard's typology of homosexual transsexuals (the ones who actually look like women and want to sleep with men) vs. autogynephiles (heterosexual man with a autogynephilic fetish who troon out later in life, they're our Zinnia Jones, Contrapoints and probably soon Ollie from PhilosophyTube). Contra made once a video where he tried to prove that autogypnephilia doesn't exist and he's actually a genuine trans woman. Rod Fleming deconstructed Nyk's video and claimed that Nyk fulfills all the typical signs of an autogynephile.
PSA Stich + Adam Friended: Centrists who frequently watch BreadTube videos and comment on them.
There are of course much more. I didn't include any people like Black Pigeon Speaks, since 95% of right-wing and left-wing YouTube channels are just of poor quality and rarely have a substantial argument that isn't easily debunked. Most substantial videos often deal with troonerism now imo. I think this is because more and more people experience peak troonerism now and just don't believe the shit troons say anymore.