The plant has a strong resemblance to pokeweed. It can get huge. The deep red purple berries are the sure ID.
hortster

Here is a link that might be useful:

It is poke. Makes a nice specimen plant. Birds love the fruit. You can purchase a varigated type.

And they will continue to grow baak because they have a fleshy root.

To remove, you'll have to do a lot of digging. But that won't guarantee a fix because remaining pieces can still sprout.

That said, you can win, though, as long as you repeatedly remove all top growth every two weeks.

Or use a translocated herbicide -- one that goes into the roots -- and repeat every time it reappears.