One of the reasons for the monetary stimulus is that in a crisis, everyone wants dollars. Which is why the dollar continues to strengthen despite all of those efforts. Additionally, significant portions of the stimulus (repo, dollar swap lines, etc.) are unwound naturally and automatically as the crisis abates. So it's not like the money sticks around to weaken the currency.
Also, increasing bank reserves from monetary policy doesn't tend to increase lending one-for-one as banks have not been reserve constrained in a long time. Lending is dominated by capital requirements and risk tolerance. So asset purchases lead to increased reserve levels, which strengthens financial conditions and increases lending (and thus Main Street consumption and investment) somewhat, but it's not like $2 trillion of monetary stimulus => $2 trillion of ketchup bought off the shelf.