countvajhula VS puni

Has anyone used symex.el without evil? I just learned it can be use with vanilla emacs (despite the 2nd word in its tagline). I also learned they have a tree-sitter branch which will expand its powers to many languages.

For working with delimiters, you might want to check out Smartparens or Puni. There are many other packages like these, but those are the two I know about.

I'm guessing the way forward here for navigation is to change Emacs' built-in sexp-navigation when treesitter is available? forward-sexp, backward-up-list, down-list, raise-sexp etc do a good job in lisp environments, and they can now work everywhere. Packages that build on these (like Puni will automatically gain treesitter-awareness.

I have never used lispy, but I have used puni for a while now, and I'm pretty satisfied with it. I am not sure that it's exactly what you're looking for since it takes a more limited approacg, but it has a lot of the same features: slurping, barfing, raising, splicing etc.

For any Lisp you want paredit or any other structural editing package (I switched to puni recently because it’s more customizable and works with non-Lisp languages too). The first three days will suck hard because it’ll feel like the tools get in your way, but once you’re comfortable with it it’ll be the best thing ever.

Afaik puni uses only forward-sexp for navigating and manipulating sexps. So if you implement a forward-sexp-function that uses treesit.el it should work without any changes.