Sealioning is a popular tactic for people arguing in bad faith. I don't think I'm arguing in bad faith, I am just trying to point out the flaw in your reasoning.
You are saying that Biden's affirmations have no value because they might be a way for him to gain popularity. First, is this any different from anyone emitting an opinion online? You could say that Mamdani, before he became the mayor of NYC, had the same motivation. In many cases, it's a good thing for someone with good ideas to gain popularity. So this means that you have to evaluate the ideas before judging the person.
Also, it's hard to guess someone's intentions. For example, I don't know what your intentions are, should I presume they are bad and automatically reject your opinions?
Finally, there is a lot of assumptions in your reply. Nobody knows if Biden will run for office, how he will act if he does, or whether he'll stab his constituents in the back.
What you are doing is called ad hominem and it's a logical fallacy.