Google's John Mueller said that sometimes "swapping out the URL can certainly help" when that URL has been 404ed or noindexed for a while. He said "sometimes our systems are so used to a URL not "working" (noindex, 404, etc) that it can take a bit of time to get back."
John added that "in most cases you wouldn't need to though."
But I guess if you are having huge difficulty getting content that was previously 404ed or noindexed back into Google's index, making a new URL for that content and 301ing that old URL to it, might be the answer.
Here is the context of that tweet:
Sometimes our systems are so used to a URL not "working" (noindex, 404, etc) that it can take a bit of time to get back, so swapping out the URL can certainly help. In most cases you wouldn't need to though.
— 🍌 John 🍌 (@JohnMu) August 6, 2020
Also, even if you didn't use the removal tools, I'd double-check there.
You can also try to force Google to recrawl it via the URL Inspection tool, submit to index or XML Sitemaps.
Forum discussion at Twitter.
