Look I learned this in school I don’t run around collecting sources for what is essentially a blip in human history.
Your teacher was not an infallible source of knowledge, and clearly was not as well versed as they should've been when teaching this subject.
Yes to a degree. It’s long been argued that fascism’s greatest strength is the speed at which decisions can be made, they will rip through everything to put their man in charge.
As you mentioned, Nazi Germany was defeated much quicker due to its centralized, all powerful leadership making incredibly bad military decisions repeatedly over the course of WWII. No one could say no to Hitler or his staff, even if people lower in chain actually fighting near the front lines had a clearer view of the situation.
On the flip side of that anarchist movements have a lack of centralization that can often paralyze decision making in a crisis.
They did have military centralization, in the form of the voluntary bottom-up command structure that you previously declared wasn't Anarchist.
Individual platoons and squads having autonomy results in the exact opposite of what you describe, as they can make decisions on the fly based on what is actually happening in real-time in front of them (while still coordinating with the larger bottom-up militia).
This is proven out even today in the Ukraine war, where Russia continues to suffer incredible losses due to their extremely strict top-down command structure, where lower level units can't do virtually anything without approval or orders from much farther up in the chain, which takes forever and doesn't allow them to respond adequately to emerging threats. Ukraine on the other hand has been willing to update their command structure from the outdated Soviet style, instead adopting the modern squad level independent decision making that the US adopted decades ago, which has made them far more effective in their ability to defend against the invasion.
part of them being overpowered was their own weakness to establish a central command necessary for wartime decision making.
They didn't want to join the Republican army for good reasons. Being under their command with no option to refuse bad orders or to recall bad commanders, especially in an Army that was quickly taken over by tankie Stalinist leaders who would likely try to use the Anarchists as shock troops to cull their numbers and leave the Stalinists more poised to betray them (which they ended up doing anyway, even as the Fascists were winning).
They also refused outside help in fear it would kneecap their revolution.
They repeatedly asked the Republican for supplies and help, but only ever received meager supplies and worn out old weapons, the scraps, essentially. The Anarchists put in a call for the Republican government to purchase more weapons for them, and suspected they never would and even seriously considered robbing the Republican bank to finally buy their own supplies, but decided to simply wait for the Republican government to do something so as not to disrupt their alliance, which ended up being the wrong decision, as the government later just gave virtually all of their gold reserves to the USSR in exchange for low quality weapons at extortionist prices, and once again the Anarchists got fuck all from it.
Logistics wins wars that’s history 101
Yes, that's true, but the Anarchists lack of logistics and supplies had nothing to do with Anarchism itself, but purely due to literally no outside force being willing to help supply them. The Allies and USSR in WWII would've been fucked if the US hadn't have been constantly supplying them with its massive, unbombable factories churning out supplies to keep the Allies supplied, regardless of their political system.