There is a website - AdguardTeam/AdguardFilters#111383 which detects adblockers when googletagmanager.com/gtag/ (xmlhttprequest) is blocked.

Unfortunately, streamingcommunity.site#%#//scriptlet('prevent-xhr', 'googletagmanager.com') doesn't work correctly in this case and video player is broken.

If I'm not wrong, it's because website uses loadend event, so I guess that adding:

const loadEndEvent = new Event('loadend');
thisArg.dispatchEvent(loadEndEvent);

here: