The problem is not AI. It is the format you paste.
Raw HTML pasted into Elementor HTML widget, or into core Custom HTML block, is stored as one opaque chunk. Nothing inside it is a block, so editor cannot touch it, and every edit sends you back to AI. That is the loop you are describing.
Ask AI for Gutenberg block markup instead. Same HTML, but each element wrapped in comment the editor understands:
Code:
<!-- wp:paragraph -->
<p>Your text.</p>
<!-- /wp:paragraph -->
Paste in code view, switch to normal mode, and every paragraph, heading, list and table is a block you can edit by hand.
Two things that saved time.
Keep block set small: paragraph, heading, list, table, image. Let AI invent custom blocks or inline styles and validation breaks, then editor offers to convert everything to Classic, which puts you back where you started.
Lint before you paste. Mine rejects inline style, script and raw hex colors, and checks that every CSS variable actually exists in theme. AI invent colors that look right and do not exist.
AI will not design better than designer. It produces structurally consistent markup fast, and structure is most of what content page needs. Editing problem is almost always the format you paste not AI