It wasn't just Trump who rightly questioned the outcome of the very uncertain 2020 election. Most right thinking Americans saw the legal issues and apparent fraud (at the very least underhanded actions of the left after election day). The "voter fraud" narrative was 100% fact that should have been properly resolved, not swept under the rug in an unnecessary rush to judgement.
Nevertheless, legally, Biden is the president, whether elected or selected. We're stuck with what happened and all the clear damage he's done during his tenure. Hopefully that will be corrected in 2024 (and without Trump -- in spite of the undeniable fact that he did a great job as president). I didn't vote for him in 2016 due to character issues, but he proved to lead effectively and well -- and did make America Great again, no dispute. So in 2020, I went ahead and voted for him for his proven ability (character was still in question) AS WELL AS all the complete fraudulent claims of the left re: impeachment and essentially wasting four years of the country's time with their TDS.