Does SPO support Linkedin link preview?
Yes, Linkedin is using the same social meta tags as Facebook. The specs are the same. If you've set a custom Facebook link preview for a page, it will show the same result on Linkedin.
How can I check the result?
Similar to Facebook Debugger, you can use Linkedin Post Inspector to check the link preview for a URL. Just enter the URL and hit Inspect. You'll see how it's shared on Linkedin.