re: OT help, dishwasher. Works fine and does NOT overflow, but

disconnect the hose from the disposal, get a bucket and put hose in bucket. Turn dishwasher on and start any cycle. It should run drain pump first. if it does and water comes out under decent pressure, then you likely have an issue in the disposal or the plumbing.

If the pumped water is trickling then you have a restriction on your pump or a clog. You can clear the line with a small snake or a shot of compressed air.

On most dishwashers you can clean the area at the base and get to the impeller. You may have to remove some screws. Some dishwashers have a separate drain pump and on many of these you can't get to the impeller of that pump, only the main pump.

At worst you need a new pump and that is cheaper than a new dishwasher for sure.

Another thing you need to check for is that at some point in the run of the drain pipe it needs to be ran at a level higher than the lowest part of the sink tub. This prevents backflow.

Do the bucket test, that at least gets you in the right direction. It's what I would do first, I run it onto a wet vac.