daily notes is not store in the same directory as org-roam-directory
Do you want the daily notes to be still in Org-roam database for some reason and exclude them only from org-roam-node-find? If so, you can use the directory as the key to exclude them — you should be able to use the FILTER-FN — see the doc string of node-find command. I believe there are some examples in this forum if you search.
You can also exclude daily notes completely from the database. See a user option — I can’t look up the exact name right now (no PC with me) but something like org-roam-exclude… I think. It works with regexp.