I was just about to do the old duplicate-text-layer-put-outline-on-bottom-text-layer-repeat-with-all-text-layers-trick when I found that Pixelmator Pro has gained the ability to apply a stroke to the outside of text. It's only a little thing but it makes me so happy.
Thanks, guys. I have no idea how long this feature has been in Pixelmator Pro but I'm so glad to see it.