Invoking extended articulations for percussion in Dorico?

Yes, you will need to create Percussion maps and their techniques for playback. This may be overwhelming when working with it for the first time, but when you get the hang out of it, it actually works pretty well.
I would advice to watch the Steinberg video about it, to find out what you have to do to get it working, but it can defenitely be done.

Edit: you may have to create an expression map for some changes as well, like different sized cymbals and gongs, or to change from sticks to bows et cetera. I've done this for my extensive VSL libraries and it works great.

Thank you for pointing me in the right direction. It's been quite a difficult process trying to get this up and running even after watching tutorials. Can't seem to get any of it working.

There's other even more "basic" articulations I'm trying to work out, such as cymbal stick taps (vs. full crash sound) and notating whether a cymbal (or drums like timpanis) should choke or left open to sustain. Kinda seems like a really basic Perc101 task, so I'm surprised it's not easily available and that it practically requires an engineering degree to set up

That must be very frustrating for you.

Dumb question probably, but did you assign the Percussion map to the right channel in play mode?
2nd, you need to edit playback techniques in setup mode for the selected instruments. Click on the three dots and click on edit playing techniques (or something like that; I'm not behind my pc right now, so not sure what they're called exactly). There you can add as much techniques as needed, with different noteheads if you prefer, but you need to add this in the panel underneath, plus in the panel on the right side, where you select the appropriate expression.