My biggest problems with vim are lack of feature discoverability and the fact that you can't change the keybindings. It's very hard to learn new things in Vim without specifically googling for them. It's highly likely that if I sat down to some online course I could learn a lot more about the Vim way of editing but I could never sit through one long enough to discover new things, so most of the things I learn about Vim come from me specifically looking up how to do certain things, not a bad way to learn, but I feel like I never got extremely proficient becasue I didn't go deep enough.
I find a lot of the keybinding to be unintuitive or not very ergonomic or inconsistent, but I also don't want to rebind anything because part of the reason vim is so useful is the fact that you get this tool with every linux install and changing things means you're no longer using The Vim. On the contrary it feels perfectly fine to tweak your IDE's keybindings because that IDE is already very specific to your needs.