There is more ways to lose a debate than just say nothing but insults or incorrect 'facts' - theres a really good Christopher Hitchens vs a creationist debate, where i believe the question was 'Does God exist?' but Chris spends the entire hour talking about how awful the god is - pointing out all of its atrocities if it did exist, all of the atrocities committed in its name. While these are all true, its easily conceivable that God could exist while being a cunt and asking for the sacrifice of children and so on. He totally lost that debate intellectually.
Theres another one where he argues with William Lane Craig. WLC, of course, has done this a million times. So he has pre-planned out dialogue trees
a dialogue tree, assuming you don't know, is a debate tactic where you lead your opponent down a pre-planned list of questions to arrive at your conclusion for you. An example would be - Do you see red cars outside? Yes. Do you see red cars near your house? Yes. Then it follows that your neighbour has a red car. The point of a dialogue tree is to bolster a dogshit illogical conclusion with logical questions.
Anyways, WLC does this the entire debate, Christopher obviously isn't prepared for it - the smartest man on the planet will be made to look a fool in the eyes of a pleb if he fails to answer a question and CH did this non stop in that debate. So he got out debated and shat on.
Both of these were formal debates btw.
Debates that aren't televised or held in arenas simply don't happen. You're talking about people that make millions a year - taking up hours of their time, plus time spent travelling and preparing needs a pay off. Debates are almost always either for charity or to sell a book. This doesn't mean the debate can't be formal. The only thing you need for a formal debate is a moderator to keep people from personal insults or talking over the other one.
Logical fallacies should lose you the argument, but they're so damn popular for a reason - they work, especially if you aren't aware of them. This is why the dialogue tree style of debate is so popular, why every single 'SJW PWNED NOOB REKT!111' video begins with an SJW saying their piece and the epic right winger
emoji running her down a dialogue tree.
The thing about dialogue trees is there is only one option - to refuse to answer. But you can't do that, because that looks JUST AS BAD as walking down the dialogue tree - you look like you just got fucking hammered. Unless you've the on the spot intellect to recite an entire argument for why dialogue trees are a dogshit way to debate, you're going to just look like a flustered idiot, panicking and stalling for time. The only thing a person needs to say is "so you're saying you can't / won't answer my question then?" and they've, in the eyes of public opinion, won.