For some reason, the option to rename layers is missing from the menu if you right-click on the canvas. It’s only available if you right-click inside the layers panel.
Thanks for flagging this to us. This feature doesn’t exist in the context menu on canvas, but we updated your topic to add it as a feature request. This way others can vote or add additional feedback. Thanks!
P.S. In case you didn’t know, you can double-click on the frame name on canvas to rename.