You are correct. As long as you meet the signature thresholds, deadlines, and other requirements in each of the 50 states, you can get your name on the ballot (in some cases this may mean creating your own political party).

It's a little late in the game though for independents to do so in time for the November elections this year... unless they're connected to a different political party.

It's remarkable to me how unified (or apparently unified at least) the Democrats have been around Kamala Harris who if I'm being honest, has not been a very impressive VP. But nobody has challenged her.

So I wouldn't expect anyone to go the route you mentioned either.