It’s better to use a custom domain or no alias at all for important personal stuff, but if your goal isn’t to be unidentifiable by the organization, then you can safely use your own name in the adresses. You will still have the advantage of spam control.
One downside I can think of is that the (government) organization will know that you use a particular aliasing service, which may be problematic in some situations.
The advantage of FreeTube is that if it doesn’t work, it can use an Invidious instance as a fallback.