Since you mentioned Pennsylvania, I expect that case to be one of the easiest to win for the Trump legal team. The mail in votes that were received after the old deadline will likely be thrown out. Whether it will be enough to overturn the election I don't know.
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Note that the Pennsylvania suit has been thrown out, like almost all of the crazy Trump suits.
https://www.foxnews.com/politics/pennsylvania-judge-throws-out-trump-lawsuit-biden-win