YouTube is exponentially bigger in reach compared to Vimeo. According to Hubspot, “YouTube commands an audience of over two billion monthly users — almost half of the entire internet-using population. Vimeo's 230 million monthly viewers and 1.9 million paid subscribers seem insignificant in contrast.”
So if you had to pick just one, then it would be YouTube. But there’s no need to pick just one.
Just upload to both. There is no downside to uploading it on both platforms. In fact, repurpose the video and share it on every single available platform, like TikTok, Instagram, LinkedIn, Twitter, Reels, Facebook Stories, etc.