The COPPA law has been in effect since 2000, yet, in the case of YouTube, is only now effecting the platform because of the recent court case that revealed Google's intentional overstepping of the law. For videos uploaded to YouTube after January 1st, 2020; the use of child-appealing media (cartoon characters, toys, figures, etc.) will have to be marked as 'made for kids,' and be acceptable for viewing by persons under 13 years of age.
Here at Bricks in Motion, we've had a general policy to never restrict content, so long as it follows the site guidelines (which are COPPA compliant) and is correctly self-labeled when linked. Strong language, violence, and even sexual themes are allowed - but only if acknowledged with the sliders on the 'submit film' page when linking. The changes to the YouTube platform only effect that website. Bricks in Motion has always supported videos linked from other sites such as Vimeo, as well as YouTube. (Which is the most popular)
In my personal experience - brickfilms benefited under the old YouTube about a decade ago - when Google employees manually chose the homepage featured videos. Brickfilms would often be featured on this page (one of mine even was) and, generally, Lego content would reach a large audience. Although the community has remained strong - with new people joining all the time - exposure, unfortunately, has declined. 2017's adpocalypse and Elsagate controversies hurt brickfilmers videos even more.
TL:DR - Things have been getting worse and worse for smaller channels aspiring to reach a larger audience - regardless of content.
I'd say that the only 'bad time' to get into brickfilming is when you, yourself, don't have enough free time to do so. Before YouTube, brickfilmers had to upload their videos to personal websites and forums for their audience to manually download and view - often on slow, pre Wi-Fi connections. Streaming and social media platforms, like YouTube, were a benefit in some ways, and a detriment in others.
My advice? Make brickfilms. If it's content that won't comply with YouTube's new restrictions, then you'll have to upload elsewhere. However, YouTube still is the largest and most beneficial platform for brickfilmers. Don't censor yourself creatively, but if you want to upload to YouTube specifically, you'll have to make sure your content is appropriate.
Otherwise, feel free to make brickfilms and upload them to other websites. Linking them here will guarantee some exposure amongst the brickfilming community at large.