Manipulated HTML loads after original page loads

[itspvty]

The cached HTML code from the Page Manipulator only loads on the webpage after the original source has finished loading, including iframes and other media.

[Ruud14]

I am aware of this,

This happens due to the required migration to manifest V3 which does not allow for the old, quick, injection method anymore.

I had to move from the old injection approach to a different slower approach (0fd38e6bc0d09ccfa7302e604b1985d8fe5a3994) which lets you see the original page for a fraction of a second (or longer depending on the page).

I have not yet found any better way unfortunately.