Personally, I just wouldn't be surprised if Huawei is actually operating cleanly on paper (in terms of back doors) out of pragmatism and foresight because confrontation with US security apparatus seems inevitable. Hence the lack of evidence from even private security researchers with no incentive to conceal. Huawei knows they're not getting into US. The PR is for 190 other countries, some of which might be five eye allies with how things are going.
The US is in panic, because not only is there a sense of crisis because the rest of the world is less and less willing to put up with the undemocratic behaviour of the US spying apperatus, this also hurts every US tech product abroad.
If I have to choose between potential future spying by china and actual in progress spying by the US, maybe I might go with china for now.
That means nothing, even if today the Chinese intelligence services take absolutely no interest in penetrating Huawei - which is laughable - that can change. If five years from now Huawei 5G equipment is used to build your countries 5G network, the Chinese gov uses their equivalent of a NSL and it's game over.
Even if today's Huawei is clean.
That's the real threat model. And that's why the US threatened 5 eyes countries to take away their access if they use Huawei equipment.