I tried to keep it away from pik (successfully) and jpeg xl (with moderate success), but in the end we needed to add yuv420/yuv422 for old school jpeg recompres

I tried to keep it away from pik (successfully) and jpeg xl (with moderate success), but in the end we needed to add yuv420/yuv422 for old school jpeg recompression (75 % of old jpegs are in this unfortunate mode). Usual JPEG XL images are always yuv444.