Sorry, couldn’t figure out how to post image or delete post…
Welcome Tobiah!
I can’t see the image you posted, but it’s possible the solution is to “force duration”, the c-clamp icon on the right panel or hotkey “O”. With force duration Dorico will keep the durations you entered and not convert them to what’s specified by the note grouping option.
Welcome to the forum @Tobiah !
In the first instance, check in Library > Notation Options > Note Grouping. Dorico uses those per-flow defaults to determine when notes are eg dotted vs tied.
You can set those options once, and all notes in the corresponding flows will follow what you’ve set. If you need to override those for whatever reason, you can use Force Duration - but I’d recommend only doing that when you’ve first checked for defaults: it will make your life a lot easier in the long run!
You can also specify beat grouping in the time signature: eg enter [2+3]/8 into the time signatures popover to input a 5/8 time signature that’s grouped in 2 then 3 quavers.