It'd probably be a good thing if Biden were replaced - it'd surely indicate that they aren't planning on stealing the election, because if they were, who cares whether it's with Biden or someone else? And I don't see Trump losing legitimately.
Not to forget they just yesterday they replaced "Master Password" with "Primary Password".
Philadelphia... besides, here's an equivalent to what you're saying: if I stab you, and then I show footage of me not stabbing you, does that prove that I didn't stab you? No. Poll watchers may have been allowed in during some periods, but not during others, but unfortunately it's a binary; either they were allowed in (all the time) or they weren't (if they weren't allowed in for even 10 minutes, that's not good enough - that's 10 minutes of cheating).