My join request has been pending for a long time

Approvals are done by that club's own admins, on their own time — it is not an automated queue, and a quiet club can take a while. Creta support cannot approve you into someone else's club.

What you can do: read the club's announcements to see whether it asks anything of new members, and if it has an open post or chat visible, introduce yourself there. If nothing happens, joining a more active club in the same category is usually the better move than waiting.