Any web application really has access only to "ephemeral" storage like cookies or localStorage when used in this manner (you could be cleaning your localStorage

Any web application really has access only to "ephemeral" storage like cookies or localStorage when used in this manner (you could be cleaning your localStorage for every session too). Switching to localStorage would help things, but until they do, you can avoid the known failure case for Element Web by not doing that. Obviously though, they need to figure out a way to reestablish encryption when the keys are gone, as long as you are willing to accept no access to history, or keeping keys encrypted server side.