Xbox insiders app deleting itself

There has to be an issue with the app itself!

If you are on Android, try clearing the app cache. if that doesn't help, try to reinstall the app.

If you are on IOS, you cannot really delete the cache, so you might want to reinstall!

If the steps above do not help, this has to be a bug that I would recommend reporting it, so it gets looked into: Provide feedback as an Xbox Insider | Xbox Support

Try reset settings in xbox itself. Will delete your account but not games.

I did reset it via apps and features dont know if there is a reset in the app itself havent found one.

If I were you I would sign out of the profile on both the xbox itself and the app, delete and redownload app then resign in

"So I deleted all consoles registered in the Insider app, I deleted the app, downloaded it again, but now I have no consoles registered in Insider app, still no option for console streaming in Xbox settings. "

You must have at least one console registered in a Insider preview ring as at this time Streaming is only available to Insiders for the purpose of testing functionality.

Check this Xbox Game Streaming (preview) support wiki on the XBox
Insiders Forum for more details.

Do they come back on the Xbox itself, or just on your phone/PC via the apps?

I've had lots of problems with the Xbox app on Windows 10 being out of sync when it comes to messages. Sometimes it'll be missing conversations that I can see on the console. Sometimes messages will be missing from conversations. Sometimes conversations
I've deleted on the console will still show up in the app.

The solution - albeit, likely a temporary one - is to reset the app. That will reset all of the app's settings to defaults and force a resync of your conversations and messages.

If you're seeing deleted conversations reappearing on the console itself, you could try removing and re-adding your account. That will remove your local saves, but they will be resynced via Xbox Live as you launch each game/app, so as long as your console
has been connected to Live you won't lose any data/saves.

If that still doesn't work, I'd report the issue via the Xbox Insider Hub and/or Feedback Hub apps.