56. "Are you dead set on having a grassy (or astroturfy) area?" In response to In response to 52
bc that looks like it could make a nice shade to semi-shade garden. Little circular walkway through it, maybe a bench at the far end with a bird bath. Mix of big-leaf plants up against the edge (hydrangeas, some of the bigger hostas, jack-in-the-pulpits, etc., maybe some azaleas etc. if enough sun) and smaller woodland plants (shade irises, trilliums, smaller hostas maybe, primroses...) toward the walkway.
Looks like you already have some hostas at the far end? Wisteria on the fence at the right? Could be trimmed up but still a nice enough plant for found material.
If you want a grass look, that looks like it could be a good spot for using thymme as a ground cover. Read something like https://www.mountainvalleygrowers.com/groundcoverthymes.htm and see. Not good for playing ball, though. And maybe expensive to do a big swath like that.
Good luck with it. If you do turf, make sure the drainage question is addressed...