Meta's second Segment Anything Model (SAM2) has an Apache license. It only does segmenting, and needs additional elbow grease to distill it for browsers, so it's not turnkey, but it's freely licensed.
Yeah, that one seems to be the closest so far. Not sure if it would be easier to create a background removal model from scratch (since that's a more simple operation than segmentation) or distill it.
I got pretty far down that path during Covid for a feature of my saas, but limited to specific product categories on solid-ish backgrounds. Like with a lot of things, itβs easy to get good, and takes forever to get great.