A better option might be to split out Tina into its own module of JS and load it on-demand with maybe a lightweight progress bar or loading indicator when triggered/required? Such as when hitting a keystroke or when a cookie or other local editor state is present?

totally! The team has making strides recently to split up the packages so that only the lightest layer needs to be loaded upfront, and the Tina UI can be loaded dynamically when in edit-mode. I'll loop in some members of the team that might be able to speak more to that.

Rewrite it in Svelte. It will be trivial, easier to maintain, blazing fast, and light as a feather. I’ll happily help!

Co-founder here. As jpohalloran noted, we're working toward fully decoupling Tina from your production site.