load blankline highlights after its setup() too https://github.com/lukas-reineke/indent-blankline.nvim/issues/754

lua/nvchad/plugins/ui.lua

@@ -54,6 +54,8 @@ return {
       local hooks = require "ibl.hooks"
       hooks.register(hooks.type.WHITESPACE, hooks.builtin.hide_first_space_indent_level)
       require("ibl").setup(opts)
+
+      dofile(vim.g.base46_cache .. "blankline")
     end,
   },