Lazy-loading `quicktex` via `lazy.nvim`

[make-github-pseudonymous-again]

Lazily loading quicktex with a custom ftplugin configuration works via lazy.nvim using the following configuration, provided you have put your custom configuration under ~/.config/nvim/after/ftplugin/...:

{
  'brennier/quicktex',
  lazy = true,
  ft = { 'tex', 'latex' },
}

Since quicktex is only meaningful in insert mode, it would make sense to load it on event = 'InsertEnter *.tex':

{
  'brennier/quicktex',
  lazy = true,
  event = 'InsertEnter *.tex',
}

But this does not seem to work, because then the default dictionaries of quicktex get loaded last.

Is there any way to load quicktex with a custom configuration when entering insert mode for the first time?