The canonical handles the indexation. Your content on your own site gets the credit, rather than the corresponding content on Medium. In theory, you're getting a bit of domain authority passed over from the Medium article. Here's an example:

https://medium.com/@w00t/the-2018-burning-man-ultramarathon-...

Has a canonical tag pointing here: https://johnvantine.com/2018-burning-man-50k-my-first-ultram...

When I search for a snippet of text from the article, the one on johnvantine.com ranks.

And you're leveraging the community on Medium, too, so there's some discovery that can happen on that end. Best of both worlds IMO.