I don't know anything about PA so I won't comment on the potential for fraud there. I will say this about ballots in WA though. As long as ones ballot is post marked on Nov 3rd the ballot is counted in the following days. That gives the USPS a window to deliver the ballot if someone votes by mail on election day. We've been doing that for 10 years and to my knowledge there has never been a problem with fraud. Kim Wyman (R) is our sec of state (directs elections) and she will probably be reelected.
Because PA is a swing state there will probably be law suits into 2021 contesting the outcome there just like there were in FL. I don't think it will matter in this election though because Biden will probably win by a margin that can't be overcome by the PA electoral votes.
I don't really have a dog in this fight because what I do doesn't matter. The election will take place and the winner is the winner, regardless of fraud, highjacked ballots, media bias, and any other unfair advantage I can think of. Just like when Hillary Clinton was robbed , somebody's going to lose.