I replied to J Bostock. To address the "wouldn't it be infectious", that mental model has the assumption of being able to actually detect transmission. That type of thinking seems inherited from acute infectious models rather than chronic disease modelling. In the chronic pathogenic model, progression of disease can be slower and causal attribution can be unassigned. To understand this point, see link below re: latency in cryptococcus neoformans, where the fungi can go dormant in white blood cells for years or decades.

https://pmc.ncbi.nlm.nih.gov/articles/PMC7324190/

For what it's worth I found OP extremely valuable.

The tenet that radiation cannot spread a fungus is incorrect. Fungi radiotrophic effects in the literature is exactly aligned with radiation making cancer worse. See cryptococcus neoformans and ionizing radiation triggering a melanin synthesis virulence loop. See the lichen that grew on the international space station. Other fungi including sacchyromyces are also included here. You can match this phenomenon to reports of mammogram induced cancers of which there are studies available.

You are correct, the fungus theory is testable.

My response, written in about half an hour, from the top of my head:

1. You aren't accounting for the ability of fungi to travel. Fungi like candida albicans can extend hyphae to extend spatially into surrounding tissues. This is why, for example, fungal arthritis is a thing, they can move over time in the body and into different areas post-invasion, so it's not just exposed areas that are expected to be affected. Cryptococcus neoformans can use the "seed cell" morphotype to go smaller to a few microns in size, so they can get into tighter spots over time. Also, c. neoformans can travel in white blood cells. Look up the "trojan horse" mechanism, unfortunately this is a real thing.
2. This is using diagnosis and age metrics so survivorship bias is possible. We don't count the people who didn't make it to the older cohorts. For an infection where disease progression is slower, time is indeed a factor, so it's expected the cancers would be different.
3. Looks like you're restating the conclusion here. But p53 is involved in the genetic repair response that fungi like candida albicans can trigger via mycotoxin damage, for example. If you elaborate further I can try to understand your point.
4. Immunosuppressed individuals are likely already on immunomodular regimes, which might include anti-fungal and other things to address the fungi that are responsible for the common cancers. The fact that immunosuppressed get super weird cancers is still aligned with the large variety of fungal pathogens. The fungi world has exotica too, we actually don't even know the full spectrum of fungal species on earth (there are too many variants). The consistency in cancer hallmarks, as well as the variations, is equally matched by the consistency of fungi, as well as fungi variations.
5. I don't know enough (yet) to respond.
6. Canadian oncologist Dr. William Makis uses a protocol with ivermectin, fenbendazole and mebendazole with testimonials posted publicly. By categorical definition, -azole class drugs are anti-fungal. Not everyone can plan, fund and execute trials, so this shouldn't be used against the fungal theory. For what it's worth Dr. Makis has participated in trials. To your other point about mass treatments of anti-fungals and an expected miraculous curing of hundreds of thousands of patients by now: Fungal infections may be localized in different areas of the body. Fluid dynamics, physics and bioavailability are some reasons why the drugs may not reach 100% coverage in the body. I know this because my ACL rupture from a sports injury needed surgery to heal, as blood circulation didn't reach the ACL directly. Some drugs may not be able to cross barriers where the fungi can.
7. Looks like an appeal to the crowd and doesn't address the fungal theory directly. Aside from that, scientific consensus can be wrong with many historical examples available.

I think the fungal theory is very likely something that oncology has missed.

Congratulations, you have entered into the legendarium @RatsWrongAboutUAP. I fully agree with you and think you will win big here. I have been trying to create a bet with Eliezer since 2021 on this same issue (I have receipts) but could not word the criteria as elegantly as you did. Now, what I wanted to comment on was expanding on one of the criteria.

The Breakaway Group. This example may not fall under any of the previous explicit examples: they are still human, they are not an ancient civilization, they are not time travellers. The Breakaway Group represents a rogue element using the cover of the national security apparatus of unacknowledged special access programs to avoid disclosures, oversight and achieve compartmentalization of tech and knowledge. This is the complicated world where the nature of these programs may not be fully revealed due to the enmeshment of the military industrial complex with the nation state, but craft and/or new technology may be revealed that still matches UFOs because they came from reverse engineering programs or recovered craft.

I would consider the above scenario satisfying the "Secret Manhattan style project with beyond next gen physics, that we had back in the 60's" criteria, partially. But there are some additional assumptions built-in, like the potential illegal nature of Breakaway Group activities (operating without proper oversight, murder to maintain secrecy as per Grusch) meaning that it is not like the Manhattan project at all. But it would still be significantly weird to cause ontological shock, so it is likely to satisfy the same. Still, worth clarification.

I am available here or on twitter @micksabox for anyone else to offer bets under same resolution criteria, if that is allowed.