On this page, OneTrust is loaded first, GTM follows. Note, order doesn't matter - see index2.html for an earlier test.
GA loaded via GTM using "Google Tag" respects OneTrust OOTB.
The GTM "Custom HTML" tag that writes the "cwcustomcookie" cookie followed this guide to respect OneTrust settings.
"cwusername" set via JS on this page has been modified to use JavaScript type rewriting.