Hey tsgolden,
Yes I don’t see it on https://devpve.wpengine.com/robots.txt either.
Here’s what to try:
1) If you’re using other SEO / sitemap plugins they might have disabled the built in sitemaps, so check that first, in case they have competing functionality.
2) Next thing to check: Under Settings > Reading, “Search engine visibility – Discourage search engines from indexing this site” must be UNTICKED. If search engines can’t index your site, there is no need for sitemaps.
3) Next thing to check is go to the permalinks page and press save to flush the rewrite rules. This should already have happened as part of the WP 5.5 upgrade, but it’s harmless to retry this and has fixed similar issues.
Best of luck!