Strategy for posting videos - single or multiple platforms?

I’m new to sharing content on social media, and I have a question about the best strategy for posting my 2-4 minute videos. When starting out, is it more effective to focus on one social media platform or should I post my videos on all the major platforms (like YouTube, Facebook, Instagram, TikTok, etc.)?

I’d love to hear from those of you who have experience in growing an audience. What has worked best for you? Cheers!

TikTok, Instagram and YouTuber are the best for shorts.