If you think Trump has cognitive decline, you're really speaking from inexperience. I would dare you (but since you won't, why bother...) to compare any recent speech of Joe's (well, that you can find... even if it's not more than a few mins...) and compare it to one of Trump's for cognitive decline. Joe is waaaaaay out in front.
If you've ever been around a good number of folks with dementia or Alzheimer's, you'd know what I'm talking about. We all get confused sometimes when we speak, and yes it does get worse with age. But that's not the same, that's not dementia.
We see Biden forgetting not just words (which he does at a rate way more frequently than Trump) but forgetting, period. People with cognitive decline can forget what you and I would assume. For example, they can pick up car keys and not know what they're for. Not just which car they're for, but that they're for a car. That's the difference. Biden has it, Trump doesn't.
What are you seeing that tells you Trump is as bad off as Biden? I watch most of everything they both say in public, and what you've claimed is just not there.