Inconsistent support for strikethrough and italics across different style packages

[eli-front]

Setup:

m1 mac
iTerm
NerdFonts: 0xProtoNFM-Regula

Issue

Italics don't appear to work correctly with certain color schemes and I am trying to understand why. For both of these, strikethrough doesn't work.

Default rebelot/kanagawa.nvim setup result

Default folke/tokyonight.nvim (storm) setup result

Default no style setup result

Showing that the terminal is not the issue

[eli-front]

For Italics / Unsupported Styles (Ex: tokyonight w/ italics)

  {
    "folke/tokyonight.nvim",
    priority = 1000,
    config = function(_, _)
      require("tokyonight").setup({
        style = "storm",
        on_highlights = function(highlights, colors)
          highlights["@markup.italic"] = { style = "italic" } # this is the important line
        end,
      })
      vim.cmd.colorscheme("tokyonight")
    end,
  },

For terminal support for strikethrough

# run the following to see term config
infocmp
# see terminal type
echo $TERM 
# add smxx=\E[9m & rmxx=\E[29m
infocmp $TERM > myterm.info
vim myterm.info # add smxx=\E[9m, rmxx=\E[29m,
tic -x myterm.info