Rudbeckia laciniata ?

Hope so! That looks like a possibility.

Looks kind of like aegopodium (Bishop's weed)

Not Aegopodium. Different growth habit, leaf shape and texture.

Could Rudb nitida be an option? The foliage reminds me of my R n Herbstsonne.

And at only one nursery I found the description that R laciniata would spread by rhizomes.

The pic shows a clump IMO, so perhaps that doesn't fit for R laciniata

I took a few additional photos. There are 3 plants. They grow from a basal rosette. I have not yet dug into the roots to see if these are connected via rhizomes.

The outer leaves of the rosette tend to be simple and not lobed.

The inner leaves tend to be lobed.

Agree with linaria that it might possibly be R. nitida Herbstsonne.