Is this really true?
n5105 (Jasper Lake) does not support VAAPI-MADI and VAAPI-MCDI methods. VAAPI-BOB is low quality.
why intel, a company with huge $$$ problems, destroys all new cpus for watching proper deinterlaced video content?
All new Intel CPUs except EHL/JSL can do proper hw deinterlacing. See here. "* EHL/JSL only support BOB DI"
The good news is that you can enable high quality "BWDIF" software deinterlacing. Switch "Deinterlace method" to "Deinterlace", that would enable BWDIF.