Myope with uncorrected far vision about 20/400 each eye. corrected 20/20. all things near and mid seem so visually overwhelming with distance rx. now?

Presbyopia: Presbyopia is a loss of focusing ability that occurs with age. A young person whose eyes are corrected for distance vision can focus their eyes for closer objects using a process termed "accommodation". With time, eyes lose the ability to focus for closer objects necessitating the need for reading glasses or bifocals. You could benefit from a trifocal or progressive lens.