Yes washing your hands is important BUT masks also work and are important if we want to get society out and about again.

You say that experts changing the requirements leaves you with no trust.
I suggest if they never changed their minds we should have less trust.
Remember this is a new virus in humans and it takes a while to understand it and what works and does not work to prevent it and even to cure it or at least make the survival rate better.

If those studying it never had a new and better suggestion then it would mean they had failed at their job to understand and control it.

Look though studies coming out in recent times when there has been some time to see what works and does not work and any I find say wearing a mask helps to control the spread.
Because some spread the virus \before or without showing any symptoms those people being masked keep the droplets, which are the biggest infection factor, from getting beyond the wearers mask.
There is some benefit to stopping the virus coming through the mask to the wearer but the main feature is the person with the mask is protecting others,

Here is one explanation including discussion of why masks were not promoted from the start

https://www.ucsf.edu/news/2020/06/417906/still-confused-about-masks-heres-science-behind-how-face-masks-prevent

Both the Centers for Disease Control and Prevention(CDC) and the World Health Organization now recommend cloth masks for the general public, but earlier in the pandemic, both organizations recommended just the opposite. These shifting guidelines may have sowed confusion among the public about the utility of masks.

But health experts say the evidence is clear that masks can help prevent the spread of COVID-19 and that the more people wearing masks, the better.