Typo3 9.5.11 wraps <p> around <iframe> (CKEditor?) - iframe

Question

I added an iframe to my CKEditor with the embed plugin.
When i try to add in iframe it works and when is save it, it works in frontend and saves it like this in the database:
<div data-oembed-url="https://www.youtube.com/watch?v=C0DPdy98e4c">
<div style="left: 0; width: 100%; height: 0; position: relative; padding-bottom: 75%;">
<iframe allow="encrypted-media; accelerometer; gyroscope; picture-in-picture" allowfullscreen="" scrolling="no" src="https://www.youtube.com/embed/C0DPdy98e4c?rel=0" style="border: 0; top: 0; left: 0; width: 100%; height: 100%; position: absolute;" tabindex="-1">
</iframe>
</div>
</div>
But when i open the editor now again in the backend the iframe is broken, when i click on source it looks like this:
<div data-oembed-url="https://www.youtube.com/watch?v=C0DPdy98e4c">
<div style="left: 0; width: 100%; height: 0; position: relative; padding-bottom: 75%;">
<p>
<iframe allow="encrypted-media; accelerometer; gyroscope; picture-in-picture" allowfullscreen="" scrolling="no" src="https://www.youtube.com/embed/C0DPdy98e4c?rel=0" style="border: 0; top: 0; left: 0; width: 100%; height: 100%; position: absolute;" tabindex="-1"
></iframe>
</p>
</div>
</div>
The config for my editor looks like this:
editor:
config:
removePlugins:
- null
removeButtons:
- Strike
AllowedContent:
- true
allowTagsOutside:
- iframe
allowTags:
- iframe
In my Page.ts i added this:
RTE {
default {
proc.allowTags := addToList(object,param,embed,iframe)
proc.allowTagsOutside := addToList(object,embed,iframe)
proc.entryHTMLparser_db.allowTags < .allowTags
proc.entryHTMLparser_db.allowTags := addToList(iframe)
}
}

Answer 1

i think my problem was that my old config in the rte.ts from my typo3 6.x version was still loaded. i added this to my default.yaml:
editor:
processing:
allowTags:
- s
- span
- iframe
- i
HTMLparser_db:
tags:
span:
rmTagIfNoAttrib: false
config:
allowedContent: true
removeFormatAttributes: ""
extraAllowedContent:
- span
- iframe
and added this to my page.ts
RTE.default.proc.blockElementList = PRE,UL,OL,H1,H2,H3,H4,H5,H6,ADDRESS,DL,DD,HEADER,SECTION,FOOTER,NAV,ARTICLE,ASIDE,IFRAME
Hope this helps you if you experience the same problem.