Microsoft will continue to support Apple Mail, they just require a higher more secure level of authentication to use your Outlook.com, Hotmail.com or Live.com email accounts with it.
Apple Mail supports it fine, unless you have an older macOS version with an older version of Mail on it.
What macOS version is your Mac currently running?
click here ➜ https://techcommunity.microsoft.com/t5/outlook-blog/keeping-our-outlook-personal-email-users-safe-reinforcing-our/ba-p/4164184
To help keep Outlook personal email accounts secure, starting
September 16, 2024, Microsoft will no longer support Basic Auth, the
method in which a person provides only their username and password to
sign into their account. As of September 16, 2024, Outlook will require
that all those with a Microsoft email account use a mail or calendar
app or the Outlook.com website which supports modern auth, such as the
latest versions of Outlook, Apple Mail, or Thunderbird.