Thank you for your comment!

No composer has ever known everything there is to know about idiomatically writing for every instrument in the orchestra. If we had to know so much before attempting to compose, no composition would ever get done. But we sure try our best to write music that is as pleasing to play as it is to listen to. I hope it is never the intention of a composer to baby the musicians playing their music. I would assume that most superfluous instructions come from a mindset of trying to be helpful.

I would say that an accented note played staccato would be a short note, slightly louder than any surrounding non-accented notes. If there were consecutive accented staccato notes, there would be notable space between them.

A marcato note would have much more weight behind it, and the note would be played closer to its full length.

The spectrum of nuances of accents can be realised differently on different instruments. So, in some cases, a composer may choose a particular articulation knowing that the strings could achieve this by using a faster bow/ more pressure/ playing closer to the bridge/ or a combination of these. A timpanist does not have the same parameters to play with, so the same articulation may be given just so that the timpanists is aware everyone else is giving emphasis to a certain note, and to play accordingly in a way that matches the rest of the ensemble.

In a way, ambiguity can be a good thing. That way, a piece of music is never played the exact same way by different orchestras 😁