This is how this solution would likely be resolved with an image. Roughly speaking, high-DPI displays have twice as many pixels per inch than their traditional counterparts. For images to look good on those screens, they need to be twice as large.
Currently, to work with an SVG or custom CSS, this would require customization which is outside our scope of support.
Well, you have options depending upon your comfort level.
The simplest solution for most of our clients is to create a PNG image twice the size of your logo (as @Joy Rex just alluded to) and upload that as your logo in the theme. You may or may not need to tinker with some size settings or CSS to ensure the logo displays at the height you want.
If you're comfortable with CSS and HTML (and our theme manager), you could upload separate regular and 2x sized images using the Manage Theme Resources tool, and then manually reference them in the template correctly (using srcset and sizes attributes).
Or if you understand SVGs well enough, you could upload those and reference those in the template as well, just the same.
Basically you have two routes:
The easy route is to just upload a logo image using the built in uploader
The longer route that gives you more control is to manually upload your files to the manage resources page, and then adjust the logo template accordingly
