I actually been a big fan of semantics highlighting for years now, and rewrote vim plugin for semantics highlighter plugin for neovim. https://github.com/hantianjz/semhl.nvim would love some feedback on the plugin.
I do like your idea of rainbow brackets and context highlighting. I will play around with those. But I general I think using tree-sitter is pretty good way to implement most of highlighting features. With more advanced features, you will need to leverage the LSP.
I actually been a big fan of semantics highlighting for years now, and rewrote vim plugin for semantics highlighter plugin for neovim. https://github.com/hantianjz/semhl.nvim would love some feedback on the plugin. I do like your idea of rainbow brackets and context highlighting. I will play around with those. But I general I think using tree-sitter is pretty good way to implement most of highlighting features. With more advanced features, you will need to leverage the LSP.