Well that little experiment didn't work.

I can sync my iPod via the old (High Sierra) MacBook Air's iTunes perfectly fine, it's allowing me to add new stuff under 'Music Video' category as expected.

Was thinking if I dragged, dropped and changed the settings (AKA 'Music Video' category) with these new hard-subtitled music videos it may have re-jiggled things on my new Tahoe OS laptop.... alas not, they don't show there at all.

So it was only the Migration Assistant that kept the music videos in place.

On one hand i have no regrets with buying the old MacBook Air, on the other hand FUCK YOU APPLE!