Jon, out of curiosity, why would you
not want IMAP? Do you only access email with one device? I guess I'm so far past using POP, with two Macs, an iPad and an iPhone that it seems crazy to even consider POP. But...different strokes and all that.
Outlook, as part of Microsoft365, certainly should handle being set up for POP - there are plenty of instructions online and Spectrum has their settings posted here:
https://www.realifewebdesigns.com/web-resources/pop3-smtp-news-servers/spectrum.asp Is there a reason you don't want to use Mail? I switched from Entourage to Mail about 10 years ago - Entourage had more issues than Mail ever has (for me, at least). Importing everything into Mail is easy-peasy, because they both use MBOX. Outlook doesn't - so the alternatives seem to be doing things like importing into Outlook for Mac 2011 or using a purchased converter, most of which seem to be in the neighbourhood of $49.
Or...just use Mail. Or Thunderbird.