Select a function name and use the right-mouse menu or hit shift+alt+H - gives you the call tree for that function in the sidebar.
I can't believe I didn't spot that before. 
I have been surprised at just how helpful VSC can be. I even managed to find a SIEVE extension to keep my syntax correct!
I had a complete reset when I moved from VSCode (which had accumulated all manner of odd settings over the years) to VSCodium. Things are working far better now. Though I have had to ditch one extension in particular - GitLens - while useful, it was slowing things down a lot and they've made it worse by stuffing more AI into it. I reset all my saved workspaces as well so as to simplify all the accumulated settings. It was a bit of a pain but long overdue and has made a real difference.
Code folding was something I've always been a bit disappointed about in VSCode. Thankfully, the Explicit Folding extension has upgraded a few times and now does everything needed. With a bit of tweaking:
Do you use remote SSH access? If so, which addon, there seem to be a number of similar ones. I used the MS one with VSCode but I see it isn't available with codium.
I did when using VSCode which has Microsoft's own extension. But I got annoyed because that wouldn't easily let me have sudo access.
In the end, I added "SSHFS-Win Manager" to my Windows machine that I use for dev work and simply mounted the whole of my servers FS to a drive letter complete with sudo access. 
This is much easier to use since it is just another windows drive. I believe there are similar tools for Mac and Linux as well. I even now have something similar for my iPhone.
I use 'SSH Client' for no other reason than it was the first I picked. Having said that, it is easy to use and provides a reliable connection.
OK, thanks.
Yes, in fact I do have most of my systems mounted into my development laptop file system. I haven't bothered with a couple of the rarely accessed ones.
I do think it is the best way. Certainly the most flexible. The VSC file manager isn't always the best thing as it doesn't show file sizes and the like so being able to use native tools and deal with other files and maybe shortcuts outside VSC is helpful.
Also, I use certificate access for SSH so access is simple.
