I’m my opinion the permenantly installed heat pumps are far superior to anything else.
However they are expensive, $2,000 or so all in and are difficukt to install needing thru hulls etc. If money
is the real issue then a window unit AC adapted to use as a hatch AC or used in the companionway
is by far the cheapest solution, they can be had for about $150 in the US.
Next are the portables that use hoses meant to go out a window, they can be had for about $300 or so, but are less efficient unless you spend more and get a dual hose model.