Regardless of the reason, calling out such behaviour is always good, more so since many millions use outlook still.

Where is the option to make sure nobody I email uses outlook?

Check the X-Mailer header in their emails. It will say Outlook.

> If Outlook is your company's email provider... the third parties are the concern of your IT department.

Still your concern given whatever information is shared about you and your job to the 766 third parties.

This. There's a choice regarding data identifying you that's made by someone who's not you.

I'm also thinking of 2FA things many corporations mandate, requiring the use of a phone number, application or both, without them handing you a work phone. Under no circumstances will I give my personal phone number to Google or Microsoft because I don't want them to link my work and personal stuff. Right now, I'm locked out of a corporate account at Google due to such refusal.

hotmail used to be a popular choice. it can be hard to completely switch email providers. Many websites still don't support updating email.

Just pay for one which sees you as a client, not eyeballs. Enable pop3 or redirect on old account. Change as many web sites as possible.

Bonus point if you get your own domain. Bitwarden and others allow creation of individual users on the fly on your domain, while a catchall on the email server collects this.

none of what you listed is 'free'. it requires time to create a new email, configuration, and learning how to use new tools.

You must be new here - "unwarranted outrage bait" describes at least 50% of HN homepage.