These are all loud.

If looking at 24" there are Whirlpool and GE made models.(Technically Miele Professional is portable but those are $5-$6K)

GE is louder and more repair prone.

I would go with Maytag Jetclean Plus Series MDC4809PA.

If looking at 18" there is Frigidaire and obscure rebranded European dishwashers.

I would go with Frigidaire FFPD1821M. Technically this is 20.5" wide but still a narrower smaller model

If you are not a single lady with a cat on disability I would skip the countertop models.

Thanks for the reply. I'm thinking I would go with a 24 inch as I'm assuming that will allow me to fit more items at a time. I have space where I could put it when I needed to use it. It's just that it would take a remodel including a redesign to get a built in one.