In hospitals, high importance is rightfully placed on correctly fitting N95/FFP2 and up – this is so that they function to spec and can be formally assumed to work like the specification indicates so they can be applied as a tool in general use by, well, by a population of staff.
This does not mean that respirators which are worn in a reasonable manner will ever be as poor filtration devices as gaping masks, especially not if the pathogen is airborne / aerosolized and operates almost purely as air flow, not droplets with mass and inertia to consider.
And COVID-19 is airborne and must be considered as airborne. There were five links, and the fifth is a collection of papers :) There is also a significant amount of detail and discussion and framing and context in adjacent tweets i all the links.
People keep dismissing this, but respirators in hospitals are very different than respirators in the hands of the general public. Fit matters more than anything else, and hospitals have staff and procedures to ensure that PPE is used correctly.
This isn't a small or theoretical concern. Even a tiny gap negates the effect of the respirator, and people don't fit their respirators properly -- in large part because properly worn respirators are annoying and hard to tolerate for long periods of time. I regularly see people walking around with KN95 masks on their faces, with massive gaps around the nose and chin. These masks are pure viral theater.
(Also, not for nothing: two of the twitter links you cite are about respirators in hospitals. the other two are mechanistic studies, which are basically useless. Every failed intervention or drug in the history of medicine has a mountain of plausible mechanistic studies supporting it. Most things don't work, but everything we try has someone claiming that it's a sure-fire solution, based on a lab study.)