Most of what you you say is credible. But it comes down to a personal choice about the balance of probabilities for where objective knowledge really resides.
I do not trust myself, as one flawed, idiosyncratic and individual brain.
I am more likely to trust the established objective view of other consciousnesses. The scientific method is (should be) a collective network of communicating, iterating, self-correcting consciousnesses, which operates according to robust rules and procedures established (evolved) by previous generations of collaborating consciousnesses. Of course, it is also flawed, but over long periods of time, it usually gets better answers than the intuition of individuals.
If I think I can drive, but I am drunk, and a good friend tells me I'm drunk and I should not drive, then I should believe them, not me.
If I think I have some medical symptoms, I tell a doctor. However, an individual doctor can be corrupted by mis-education, ignorance, their own psychological issues, or their own financial gains for various treatments. So I ask multiple doctors, but they may have a consistent bias. But if I don't trust any rational explanation of my symptoms, then yet another doctor may diagnose shape-shifting hypochondria or paranoia against doctors. Who to believe? It's not obvious, but it's not obviously me over all others.
Still, even in your case if you slowly strip down the layers of your analysis, you will notice that it necessarily boils down to few things that you know directly and you can't build a proof for them because any other proof will be build on them being correct.
Look, there are things that you know are correct and you can't make a proof for them (even the "I think therefore I am" is a circular reasoning, the real info is in "I" itself), and in your case you believe a lot of things about yourself and world you live in before you can really start to depend on the higher order conclusions that allow you to trust your friend or your doctors.
It takes a 3rd party, someone outside the situation, and possibly some time after the fact, to decide what most approximates objective truth.
I don't trust myself here and now, I could be drunk or deluded, or vain, or biased, or self-obsessed (most people seem to be that way).
I don't trust my doctors, they could be under-educated, or self-interested to overtreat me, or publish more papers on anti-doctor paranoia, and self-obsessed (most people are that way).
I only trust some averaged, collective, rational, longer-term, reflective, investigative, independent, reviewed, challenged, criticized and doubted process to get closer to truth.
> I only trust some averaged, collective, rational, longer-term, reflective, investigative, independent, reviewed, challenged, criticized and doubted process to get closer to truth.
We're probably repeating ourselves, but this averaged process still has the same bottleneck which is your direct experience and your trust that your experience is true and contradictions are impossible indeed etc... You'll never run from this bottleneck no matter how you put this process.
I'm not debating wether we should trust the scientific process, I'm just saying to reach this stage there are lot of premises that should be established and thus the scientific process can't dispute them otherwise it will be killing it's own credibility at the same time.
Again, if I was delusional about my direct experience, then who can say then 1 + 1 really equal 2? No one can know.
I do not trust myself, as one flawed, idiosyncratic and individual brain.
I am more likely to trust the established objective view of other consciousnesses. The scientific method is (should be) a collective network of communicating, iterating, self-correcting consciousnesses, which operates according to robust rules and procedures established (evolved) by previous generations of collaborating consciousnesses. Of course, it is also flawed, but over long periods of time, it usually gets better answers than the intuition of individuals.
If I think I can drive, but I am drunk, and a good friend tells me I'm drunk and I should not drive, then I should believe them, not me.
If I think I have some medical symptoms, I tell a doctor. However, an individual doctor can be corrupted by mis-education, ignorance, their own psychological issues, or their own financial gains for various treatments. So I ask multiple doctors, but they may have a consistent bias. But if I don't trust any rational explanation of my symptoms, then yet another doctor may diagnose shape-shifting hypochondria or paranoia against doctors. Who to believe? It's not obvious, but it's not obviously me over all others.