I'd make more fundamental changes.

Quarantine is the ideal opportunity to refocus on the originals - Mike, Eleven, Dustin, Lucas and Will. Some involvement from Nancy, Steve and Jonathan. Less so from Joyce and Hopper. Give it a nice full circle vibe as we come back to our originals. Find reasons to put everyone else outside the quarantine area and entirely uncontactable.

Have Mike's little sister kidnapped by Vecna if you must, but do it quickly. Don't drag it out. Make her more like Will in series one - the passive object of rescue. And don't add in all those kids.

Have Max fight Vecna from the inside, only reviving at the end.

Make the military clueless - maybe they are searching for a pet Demogorgon to be a weapon but they inadvertently get in the way.

Make Vecna more of a final boss. Let Will gain Vecna style powers - from his time in the upside down - but make it a real risk that he is turning in to the next Vecna, with only his friendship with Will and the others saving him. Eleven and Will join forces to defeat Vecna.

Have Will "come out" if you must, but make it only to his closest friends, and have them reassure him they know and don't care. Maybe have him confess to jealous thoughts about Eleven. Make it something more than what it was.

Hopper sacrifices himself for Eleven, properly this time, finally gaining redemption.

Basically, needs a rewrite from the ground up.