Why not all three? If you are recording the content, you can repurpose it for all 3 platforms and see which one will get you the views or traffic.
You can also link all three of them so people can follow you on all 3 for different reasons, considering attention span is different (especially short on Tik Tok).
Beyond using these platforms, I would say to start a blog or a professional site to drive people there. Youtube, Instagram, and Tik Tok are basically like renting space on someone else’s land. They are great ways to get people looking at your content, but you have to bend to their rules, and the slightest change to the algorithm can hurt your views. If you own your own site, you can build something on more solid ground.