We are on the same situation on eswiki. Nobody can edit. What I saw was a massive problem on Meta: everyone's accounts look like were hacked and started adding nonsense and deleting almost every page. I wonder if the situation at Meta is related to this incident.

https://wikitech.wikimedia.org/wiki/Special:CreateAccount indicates the following when I'm not logged in these wiki: "You're required to choose a shell account name. It must start with a-z, and can only contain lowercase a-z, 0-9, and - characters." the indication it's found under the parameter of the e-mail address. And if I don't have a "shell account", appears an error message: "Your shell account name is invalid. It must start with a-z, and can only contain lowercase a-z, 0-9, and - characters."

I want to keep my history of activities of this account, but using my new name. It is likely complicated to me about the change of settings in the external accounts section. If I need a LDAP account, what is the "shell" account and how can I create/obtain that? (apparently I need a "shell" account to create a Wikitech account). And also, if I have a LDAP account and I'll remove the old MediaWiki user, should appear an option to add the new MediaWiki user?

Okay

Now the process is done after waiting for some hours. All CentralAuth acounts now have the new name: https://meta.wikimedia.org/wiki/Special:CentralAuth/Qehath

Huh, okay. Despite the ï, perhaps with the "i" should work then here? (only here, in the wikis I've wanted to use the "ï"). At least can be changed in my profile the link to the "MediaWiki User: Ks-M9" to "MediaWiki User: Stïnger"? Thanks.

It is still erroneous to re-create my old name or no? affects in this project? My current name still exists in MediaWiki: https://www.mediawiki.org/wiki/Special:Log/St%C3%AFnger

No. I've re-created my old name in this log: https://meta.wikimedia.org/wiki/Special:Log/St%C3%AFnger ; I've re-created the name to avoid usurpations and the page showed in MediaWiki is a re-directed userpage of my old name to my current name in Meta.

I'm also looking this process (at the link given by @Cyberpower678) and it seems to be failed in Meta: the rename progress indicated that "failed" (and not "Done") in Meta-Wiki. How it can be fixed? And also the failed renaming progress at the mentioned project also stopped the renaming who are missing in the remain wikis.

Now it is just done. So, thanks to all!

The following accounts that I've mentioned on MarcoAurelio's talk page are now vanished (or deleted) from the CentralAuth: