Resolution loss by chromatic subsampling: is there a workaround?
No. Almost all video on the planet is limited YUV420 (all Blu-rays, even HEVC ones with Dolby Vision, all Youtube, only some satellite FEEDs not for consumers use 4:2:2). Sorry. Of course, there is RGB and even mathematically lossless mode in all common encoders, H.264/AV1/VP9/HEVC... For lossless AV1 see https://trac.ffmpeg.org/ticket/7600
But, alas. It is not used at all.
Only Dolby Vision in profile 5 that is not HDR10 compatible (it uses IPTPQc2 color instead of YCbCr and FULL RANGE) can be good enough for you. It still uses 4:x:x chroma but because of new encoding it is much better looking!