The nature article makes it sound like a lot of the options listed are being tested because there's some evidence of some effectiveness Vs in the story OP posted, it sounds like the mechanism is much better understood.
The Nature article actually mentions the drug in question - camostat mesylate - as one of the TMPRSS2 inhibitors under investigation. (And given how often "this should work, for sure!" drug trials fail to pan out, I'm not sure that "this works in theory, here's why" is that good of an indicator)