Possible to somehow move folders from gmail to icloud mail account?

Create either local folders on the Mac or imap folders in iCloud on the Mac. Select all emails in a gmail folder and copy or move them to the folder you created for it. Once done, disable the gmail account in Mail's preferences. This will let you see if everything is ok where you can just re enable the account if necessary. Once you are satisfied, you can delete the gmail account from mail. You can also clear out the gmail messages at their website if you hadn't so within mail.

You said you have the gmail accounts set up in Mail. Do you see your gmail folders in the sidebar? Are your gmail messages in in inbox, or do you have other folders made in gmail?

If your gmail account is not expanded in the sidebar, put the cursor on the account and click the Show button that will appear. All other IMAP folders within gmail will show except for the gmail inbox, which will be listed in the Mail's main inbox.

Do you know how to create mailboxes (folders) in Mail? To create a mailbox, select the + sign at the bottom of the sidebar. In the pop up box, select the location (On My Mac- local folders, or select the account such as iCloud for IMAP mailbox). Give it a name and click OK. The mailbox will be created in the location you chose.

To Continue:

Choose copy messages from gmail to your new folder. To do so:

Open a gmail folder. Select a message in it. Hit the command key and the A key to select all messages within the folder. Once all messages are highlighted, right click over the message list and choose Copy To and select the location or account and the folder those messages will go to.

The messages will be copied to that new folder you created.

Do the same for other folders. Verify that the messages are copied to the new folders.

Once completed, open Mail's preferences and select the Account tab. Select a gmail account in the sidebar and choose the Account Information tab. Uncheck the box to enable the account and it will be removed from Mail, but will still be in the Account list in preferences. If you decide that you made an error or something isn't right, you can go back and check the box to enable the account and it will be put back into Mail.

Once you have deternined that everything is ok, you can go back into Mail preferences/Accounts, highlight the gmail account, and delete it by clicking the minus sign at the bottom of the window.

If you have more than one gmail account, you can do the same for all accounts.

Thanks for the nice comments. I wish I were a genius. Life would be much easier lol.

Happy to see you got it sorted out.

Happy to help