WHO's legitimacy is declining after their approach on china and the general covid19 situation. people seem to think the WHO tried to downplay the severity

I see nothing in WHO’s actions that suggest they are downplaying things. If anything, WHO has repeatedly issues warnings for western countries to do more.

In my opinion, the distrust in WHO just reflects poorly on the people who are distrustful. They are so hell-bent on confirming their world view that China must be the bad guy, that they would rather believe that the WHO is corrupted than accepting the facts.

You can lead the horse to the water, but you can't make the horse drink the water.