I'm starting to wonder about the whole purchase digital or physical media thing. I pre-ordered Prodigy Episodes 11-20 and also the Picard complete series, but I wonder if it's ok to buy them on Itunes since my blu ray player is old fashioned. I know people say you don't really own it, and they can let it go at any time, but it is still the Itunes store, and not Paramount Plus which did cut Prodigy. Also, the Discs for Discovery are pretty expensive now. Or just my whole blu ray set up is so antiquated that I would prefer just to get the better quality.
I-tunes is OK for music (m4a-files) because those can be downloaded and they don't use DRM anymore. If the same is true for the video files, then by all means go for it. If, however, you cannot download them to a local device/HDD or if they need to "phone home" before you can play them, be aware that what they term as "buy" is really a lease of unspecified length that the vendor can terminate at his leisure and at any time (even though this is probably illegal at least under EU laws).
It's not 4K and I think it's more than 10 years old.
I don't think that's a problem. 4K discs are expensive and rare, and quite often even 4K discs are upscaled versions of full HD masters rather than "true" 4K (Passengers, Dunkirk and Blade Runner 2049 are examples of movies that were mastered in higher than full HD quality, but even some major movies nowadays are finished in full HD due to effects work or other compromises).
Generally, even old Blu-ray players should still offer exactly the same quality as their newer cousins, if we're talking regular Blu-ray. Which is the only thing you can get Prodigy on anyway (animation in 4K would be ludicrously expensive, but Prodigy is gorgeous full HD on disc), other than the obsolete DVD format.
Blu-ray generally is a stable format, and even the PS3/PS4/PS5 (and the xbox equivalents of the latter two) play blu-ray (the versions with optical disc drives, obviously). And cheap players generally give the same image quality as those with more bells and whistles (outside the 4K players).
At most, an older blu-ray player may need a firmware update to play some of the newer discs, and only if those come with a newer version of the copy protection scheme that isn't known to the player yet.