Option to change name shown for others in my Direct Message list

I would like to change the name that I see for another user in my direct message list. For instance, there is a user called AMA, but I know her by the nickname she uses on a server we have in common, Aibhilin. I would like to see "Aibhilin" instead of "AMA" in the list of users with whom I have DMs. Another example involves a friend who keeps changing her Username AND avatar/picture -- I often can't identify her, or find her without looking for the one I DON'T know. I would love to just be able to set my DM with her so that her name there shows up as "Lady Blue" -- then, I'll always know that entry is for her, no matter what she does to her own username or avatar/picture. I just read an article from May 2020 that says you can change names of DM's with groups, but not with individuals. I would like to be able to do this with individuals as well. Thanks for all that you give us!