masses of dock leaves in garden?

hi, this is my first time posting in here so unsure if this is the right place to ask. however, maybe like 3-5 years ago my grass in my garden died off (due to having female dogs and not taking great care of it), we attempted to grow new grass using seeds multiple times but it never worked. now the whole garden is covered in giant dock leaf plants (pretty certain that is what they are). does anyone know why this is? and does anyone know how to get rid of them all, we have tried multiple weed killers, ripping them out the ground, yet nothing has worked and they continue to grow back when spring hits. we plan on getting artificial grass once we figure out how to get rid of the docks so growing the grass back isnt a massive concern. thank you for any replies/advice!