Reliable self-tests for H Pylori, and other questions

TLDR: see question 1.

Background: I had years of chronic gastritis, ulcer pain and other symptoms that led to symptomatic iron deficiency anemia, all caused by H Pylori (hereon HP), which I resolved a few years ago with antibiotics, PPIs and iron pills. I've had a few re-tests since then (including 3 breath tests and a follow-up endoscopy), which were all negative. But it is not ideal to continue using these methods to retest, for reasons I mention below.

AFAIK a lab-ordered HP test is only available three main ways:

a) requisition via a doctor (insurance covers, but doctors don't always approve, and it takes more time due to the extra appointment);
b) on-demand test via a major lab (but it's a relatively high cost per test; e.g. $200 for the breath test at Quest, which I think is the only on-demand lab option available in NY);
c) endoscopy (most invasive and time-consuming; overkill if not exhibiting long-term symptoms).

Also, although the breath test is promoted as non-invasive, the least invasive option is actually a stool/fecal test, as nothing is ingested or goes into the body. The stool test still has a relatively high rate of accuracy vs. a blood test. But it seems stool tests at major labs are not available on-demand.

This brings me to my main query:

1. It seems most if not all HP home/self-test kits on Amazon, or sold "OTC" online, are stool tests. But which are reliable/accurate? How can I be sure a kit is not fake? Anyone have any experience or advice on this? Are there alternatives to all of the aforementioned options to be aware of?

Also, I have other questions about HP I've wondered about but haven't found clear answers for, so thanks if anyone is able to help with any of these:

2. How long is the typical incubation period for HP if symptoms were to appear? Initial search says symptoms can appear 3-4 days after infection if it doesn't remain silent. Any elaboration or variation on that?

3. To what degree is an HP test sensitive to HP concentration or symptom status? For example, is someone with silent HP (or HP where symptoms haven't begun) likelier to falsely test negative than if symptomatic? Is there a demonstrable time to wait after infection (e.g. a few days) before testing to reduce the chance of a false negative?

4. If HP is present but tends to test negative, is this due to a low concentration? For example, some may see HP in a GI map but test negative for it via a breath test.

5. Is a low concentration of HP (with or without a tendency to test falsely negative) necessarily an issue if it very rarely or never causes symptoms? E.g. would taking antibiotics to nuke the gut biome be a net positive or negative in such cases?

6. Can chronic silent (asymptomatic) HP still cause metaplasia/cancer, or is chronic inflammation (gastritis, ulcers) a prerequisite? Is it possible for chronic GI inflammation to be rarely or never symptomatic yet still cause damage?

7. Can HP survive below the stomach (small intestines, colon, etc) without necessarily being in the stomach?

8. Is there any substantial evidence the body can eradicate HP naturally? Via antibodies upon infection, natural remedies, etc?

9. If reinfected, is there any downside to retaking antibiotics? (In addition to the issues of taking them at all; e.g. depletion of good gut biome). Is antibiotic resistance more likely on retaking, or is resistance unlikely if it worked the first time (as I understand there's a genetic component to antibiotic efficacy).

10. I read that HP is in its coccoid form in water but it seems unclear how infectious it is in this state. Any more detail or clarification on that?