Can I use the same link in bio page for Instagram, TikTok, and YouTube?

There's no reason to run separate pages for each platform unless your content is genuinely different enough on each one that a shared page would confuse people, which is rare. One page, one address, pasted into the bio field on every platform you post to, keeps things simple and means you only ever have to update one place when a link changes.

If you do want to know which platform sent you a given visitor, that's a job for tracking, not for separate pages. On Briklyst, every link on your page is its own tracked redirect, so your stats page shows clicks per link and when your audience shows up, which tells you more about what's actually working than splitting your page three ways ever would. Keep the one page, and spend the effort you'd save on making sure the link is actually in all three bios in the first place, since it's easy to update one platform and forget the others.