Vecna should've been captured by the military

Vecna should've been the one in the containment room in the military base.

It would've done so much to improve the final season, like:

1. It would perfectly explained why the invasion didn't happen shortly after S4. Them keeping Vecna suppressed literally stops the Mind Flayer connection and tears (we know how powerful psychic connections are in this show).

2. It gives the military more credibility and authority.

3. When Eleven and Hopper try to kill Vecna they accidently end up releasing him (maybe Hopper turns off the suppression field for a brief moment, which Vecna uses to break free). At that moment the hive mind connection is reestablished and the Mindflayer gives Vecna a massive power boost.

4. They can still keep all the Will getting power lore. Vecna can still do his Darth Vader entrance etc.

5. It gives a reason for the Mindflayer to be more present in the final season. It would be established as the real power source, which it is, but it still needs Henry's psychic connection with Earth to conquer it.

6. They can still keep the bridge theory of the Upside Down.

Am I crazy? Did I miss anything crucial?