Comment by jonsneyers

Last time I tested, libjxl e1 had a better compression ratio than default libpng, while being two orders of magnitude faster. See https://cloudinary.com/blog/jpeg-xl-and-the-pareto-front#the...

The point of reference here is not PNG but lossless JPEG, which was the best available option in DNG before version 1.7 of the DNG spec. Lossless JPEG compresses worse (but faster) than PNG.

I don't know how HALIC works but if there is no FOSS implementation available that seems like a no-go.