NixFifty's Discord Integration is the one I've settled with. I've used them all, and the other plugin's support is either lazy and doesn't care or makes you feel belittled for simple questions.
If you want a great Discord integration plugin for your Xen site I highly suggest this one. There's a few small quality of life edits that I've suggested like adding the user's Discord username automatically in the username field and editing the automatic post to Discord, but other than that it's probably the best one. I've fought for answers with the other Discord Integration plugin developers and NixFifty hasn't ever given me an issue.