Is your feature request related to a problem? Please describe.
D8 ships with https://www.drupal.org/project/big_pipe in core:
https://www.youtube.com/watch?v=JwzX0Qv6u3A
Describe the solution you'd like
I happened to come across https://github.com/turbolinks/turbolinks, which is a ~37kb js library that seems to be doing a similar thing.
Describe alternatives you've considered
There's https://www.drupal.org/project/refreshless (initially https://www.drupal.org/project/turbolinks but changed namespace after library authors' request) that implements this, but it's D8 only :
RefreshLess makes navigating your web site faster by only loading the parts that change between pages. Uses the ideas behind Turbolinks technique (pioneered by Rails). But it goes further: thanks to Drupal 8's architecture, we're able to automatically figure out which parts of a page change. So, we only need to send the parts of the page that actually change.
When clicking a link that points to a URL within the Drupal site, we then keep the current page, but just swap the parts that change between the current page and the next. This means less data on the wire, and — most importantly — less work for the browser.

Recent comments
Worked like a charm! Exactly what I envisioned... now I can edit the ruby text right in the editor, sweet:) Thank you! For those who may have a similar issue, try TinyMCE, create a new "text...
Specific tags to work in CKEditor 5
Yes, you can use TinyMCE on some content and CKEditor5 in others. There is no problem having both enabled on a system.
Specific tags to work in CKEditor 5
Thank you both for your suggestions. Yeah, I'll give TinyMCE a try... better than trying to fight that behemoth CKEditor 5. The TinyMCE page says it can "co-exist with CKEditor" which is...
Specific tags to work in CKEditor 5