If your instance is explicitly allowed by Twitter/X, a video player will be embedded in the Twitter feed on PeerTube video share.
If the instance is not, we use an image link card that will redirect to your PeerTube instance.
Check this checkbox, save the configuration and test with a video URL of your instance (https://example.com/w/blabla) on https://cards-dev.twitter.com/validator to see if you instance is allowed.