What I’m trying to write is, in 5/4: 1/4 rest, 1/4 note, 1/2 note, 1/4 note. The half note beginning on beat 3 gets split into two tied-together 1/4 notes. In the Notation Options, I’ve set ‘Notes starting after the start of the bar of multiple beats in duration’ to ‘notate as single note’, and this fixed the same issue in a 4/4 bar, but not in the 5/4.
It seems like your subdivision (beat group) of the 5/4 meter is 2+3. Select the time signature, press Shift+M (to input the meter again), type 3+2/4 in the field and press Return. After that, go to the bottom panel (properties) and switch the Numerator style to “Number” from “Beat group”.
If indeed the beat grouping of your 5/4 is e.g. 3+2 but you want to notate “against” it (the 1/2 note crossing the beat group border), input the 1/2 note again with the Force Duration (O) (left hand panel) active: that prevents Dorico splitting the note to two tied notes according to the beat group.
Good call, thank you for this info. And you’re correct, my keyboard layout is Finnish/Scandinavian, and the square brackets don’t even show up in the Shift+M pop-over when I try to input them with the normal way (Alt+8 or 9, whereas normal parentheses are Shift+8 or 9).