There appears to be a certain element of mystery to this, with many people having asked similar questions (either from the perspective of someone who's posted reviews or from that of a business owner who's expecting some). e.g.
https://support.google.com/business/thread/122612107/how-long-does-it-take-for-reviews-to-show-up?hl=en
There seems to be no clear answer. Google's own support page doesn't seem to help much either:
https://support.google.com/business/answer/10313341
I suspect though that Google might not automatically make reviews from new accounts publicly available, due to the activities of people who get paid to create lots of different accounts in order to leave loads of positive reviews for particular businesses. Simply staying logged into your new account for a while (and possibly using other Google services, such as YouTube, from it too) might help to fix the problem.
In the meantime, remember that you can leave reviews for businesses in the hospitality sector (such as pubs, restaurants, hotels and tourist attractions) on TripAdvisor and for almost all businesses on TrustPilot.