Personally, if I were Biden, I wouldn't go in person, and just have Harris or a Cabinet member (maybe someone with no Presidential ambitions, like Garland or Austin) deliver the State of the Union.
If Biden gives a damn about his public image, this would be a terrible idea. The idea behind the SotU speech is that it's a chance for the president to connect with their government and, at least for contemporary addresses, the people. Biden hiding behind his VP or some relatively unknown cabinet member would definitely give off a message of opaqueness, and Biden's public image is currently too fragile to consider such a risky move. Any dumb gaffe that Mr. You-Know-The-Thing would perform would do far less damage to his public image than pussying out altogether.
Biden's also running a much higher risk of getting murdered than any President before him, and multiple House members openly carry guns on the House floor (Boebert for example). What's stopping one of them from openly shooting him during the State of the Union?
