This is where I shine.
You can cut way back on effort required when swimming if you have proper form. If I was training from a non-competitive background, I'd probably spend 50% of my time working drills for form, and 50% doing intervals (start with 25yds at a time, then work your way up to 50s and 100s).
If you're googling for drills or workouts, check out some sites geared towards triathletes. A lot of them are adults who come from a non-swimming background, so they hit the mark pretty well in my opinion.
Not certain what the swim requirements are, but I seem to remember a deep water jump, treading water/floating, and a short (50yard?) swim. IMO, if you can swim pretty good the rest should be relatively easy. Becoming a great swimmer might not be the best use of your time depending on your ship date though.
The requirements to pass don't seem too strenuous, but I'm FY22 so I have the time for sure. I think it'll help avoid some of the impact I'm taking from all this damn running too lol.