After posting this, I have searched Google and tried lots of free e-mail services (I did so before, probably two years ago, but I could not find a good one back then), and I think I found one.
It is free; did not have phone verification. There is free and paid, but I think free is good enough. Free version provides 5 aliases, and IMAP4. Paid version supports POP3. I am not sure about the detailed differences between IMAP4 and POP3, but when I opened the Windows Mail app, clicked add account, clicked Other account (POP, IMAP), it asked me to type the e-mail and password. I was going to type the IMAP4 information, but Windows Mail automatically configured it without further input, and I could successfully send a test e-mail within Windows Mail to my own Mailo account.
Another one I found is https://www.msgsafe.io/
No phone verification. It has free and paid. Free provides 10 aliases. It has no POP3 or IMAP or anything but it has automatic forward feature. Free allows 100 forwards a day. I can set the e-mail automatically forwarded to my main e-mail account.