Hiii Heather Quitos ๐๐ป ๐ I've worked quite a bit with ITDMs and (as always) I think this varies depends on what the act of advocacy. As you mentioned, I've seen better engagement rates for more "behind the scenes" programs like advisory boards and early feedback programs.
For external-facing opportunities, I've had luck proposing a customer story where it's them (the admin/ITDM) and someone from a different department (the daily user/BDM). For things like video stories, having a colleague who is more outgoing do more of the talking helped warm the IT folks up a bit. I'll see if I can find examples to share, but lmk if you want to chat further, just send me a DM!