Resolved - I was editing .obsidian.vimrc on my vault that was located in a different location.
I have the same vault on DropBox and iCloud. I recently moved it to iCloud so that I can continue to work on Obsidian mobile … Anyway, I was making a change to.obsidian.vimrc on my Dropbox vault, but opening up the vault on iCloud.
For others that may encounter this issue, one of the things I found helpful was to type in the command in obsidian.
So, in obsidian, I typed in : imap jk <Esc> and verified that this worked. When it did, I found it strange that the change was not persistent when obsidian restarted. So that’s when I realized that the change I made was not the right .obsidian.vimrc file.