You are right that many people believe it did. And that's a huge, huge problem.
Can you explain any evidence at all that would convince you?
As I wrote above, for future elections:
"Ink the fingers, since we're 3rd-world now. Have ID, just like India and Mexico do. All votes must be cast in person. Take extra pictures when voting (face, fingerprints, iris, retina), to better enable prosecution of misbehavior. No machine goes on a network. Every machine is observed by multiple unrelated people (don't know each other) for the entire time, starting from verification that it is empty and continuing until all recounts are completed. No excuses."
There was no legitimate excuse for destroying what little election security we had. You wouldn't have done that if you wanted to hold a valid election, but you wanted to "win" at any cost.
Some ominous words slipped out of Biden's mouth when speaking to voters in Michigan: "I don't need you to get me elected!"
> Can you explain any evidence at all that would convince you?
And your response (TL;RD): "no".
You've drunk the cool aid, and it's a religion for you. I'm sorry for the state you have reached.
Ironically, Biden supporters have a better argument for believing in fraud conspiracies, given that Trump over-performed significantly compared to expectations in both of the last two elections. One man's "oh the polls must all have been wrong" is another man's "there were millions of illegal votes."
This is a scary time for the country. I sincerely hope this is just a personality cult and will fade along with Trump. Garden variety issue politics are at least halfway rational.