I'm getting a message in New Outlook that says ""Delete copy of migrated data from Legacy Outlook to free up space."

OK, well here's something helpful, though I see a few contradictions or ambiguities in the page.

https://support.microsoft.com/en-gb/office/about-on-my-computer-folders-in-outlook-for-mac-c91b8729-924d-4c25-a5f6-38883d0f763d#:~:text=Tip%3A%20To%20show%20the%20On,My%20Computer%20folders%20check%20box.

1. "For IMAP and POP accounts, items other than email messages are stored on your computer, not on the mail server." --> Note that it says ITEMS OTHER THAN MESSAGES. Further down it states, "If you have one POP account, messages are downloaded to the On My Computer Inbox. If you have multiple POP accounts, all messages from those accounts are downloaded into the same On My Computer Inbox." SO WHICH IS IT, MESSAGES OR NO MESSAGES?
2. "If you have only Exchange account in Outlook, the On My Computer folders are hidden by default." --> Not true from my experience. I just set up a test MacBook with a new O365 installation with NO POP account and the On My Computer folder is there. I presume an Office 365 account is an Exchange account (in the cloud), or is it considered an IMAP account?

So if I understand the gist of this folder it's only for non-synced items (messages??) from POP and IMAP accounts AND it's basically a misnomer since the items/files don't really live on your computer according to their documentation: "The “On My Computer” label indicates that the items in that folder are accessible only through the Outlook application, not through the Finder on your computer. Although "On My Computer" might suggest that you can find these files by searching your computer, the label only signifies that the items in the folder are not on a mail server."

ARGGHHHH

There is a folder in the "New" Outlook for Mac named "On My Computer" but it doesn't exist in the Windows version of Outlook. Given O365 (or whatever Microsoft chooses to name it this year) is entirely in the cloud I don't understand why it even exists for the end user. Very confusing. I set up a test MacBook to see how I can respond to my CEO asking for help on the annoying prompt and I do see an option to revert to the legacy Outlook, but I'm running an Office update first and it's been sitting there for a half hour so far, progress indicator at about 10%... hmmm....

This post may be helpful to some degree: https://answers.microsoft.com/en-us/outlook_com/forum/all/folders-on-my-computer/63c44a36-5021-4aec-b873-8441dccef19d

No one knows...it's a secret.

Jokes apart, I have been looking for clarity since the post began. Reported some observations where it helped.

I don't know where the "On my computer" folder is - on a Macbook Pro with Outlook

Well... here we are in mid September and the original "Microsoft Agent | Moderator" has not replied to a single question after her initial (ambiguous) post. Many pertinent questions have been posted and everyone is still in the dark. Today, my CEO sent me a screenshot of this prompt and is asking me what she should do. As an MCSE I feel abused, Microsoft has dropped the ball for professionals again. We are not consumers, we are a corporate business and need effective guidance, And yes, real businesses do have Mac products in the mix.

HEY MICROSOFT: What should I tell my CEO??

1. Go ahead and delete your old data and hope you lose nothing.
2. No, don't delete, just ignore that annoying prompt every day for the rest of your Outlook life.
3. Ask someone else, your Sr. IT Manager doesn't have a clue.

I use Outlook on Windows and tried switching to the "New Outlook" recently and immediately switched back to legacy. Honestly, I don't know how MS can punitively impact their business customers so regularly and remain popular.

Any updates from the community- the people who are directly impacted by these bad decisions?