filling a bar with the appropriate note value

Since Dorico is designed to provide the most logical notation for any rhythmic value with respect to a particular meter, is there a simple way to quickly input a note that fills an entire bar, e.g. I set the meter as 7/8 and I want to input a note that fills that bar?

Not exactly. You could enter a place-holder note (of any value) at the start of the bar, then select the bar, then use Write > Edit Duration > Extend to End of Selection (which you could assign a shortcut key to).

thanks - I’ll try assigning a keyboard shortcut

This isn’t directly addressed to your question, but is another option that I can see being very relevant and I find useful. There is a command to increase the duration of a selection. The command is shift + alt + right arrow key. Left arrow key will decrease the duration. The command works on notes as well as basically any item with a set duration of effect, like slurs, hairpins, 8va lines, etc.

I find it easier sometimes to just click a note and use that to adjust the rhythmic value until correct. It’s not necessarily one click but you’ll find uses for it.

Thanks, Robert, it’s good to be reminded of how useful that key command is.