Some people will be miserable no matter who is running
Trump’s very obviously much less mentally competent than Biden. Biden rambled a couple of times. Trump rarely forms a coherent sentence at all.
I’ll say that Biden sounds less competent at a glance. Like if you watch and go through his mental process, you understand how the mistake he made happened but you know the substance of what he was trying to say.
Usually Trump says stuff that, on the surface, sounds like maybe something but if you try to think about it it makes no sense.