see my hack above.

Select that you want to view your profit/loss for 05012019-05312019.  When you do this, the compare another period now has a custom option.  Select custom and type in the date you really want to compare against (like 05012019-05312019.  Then fix your original dates to the current data you want to see (like 05012021-05312021).  The custom button stays and you can select whatever old period you want.   You may have to play with it to get your custom old date to stay but once you figure it out....easy peasy!