Not a great swimmer and thinking of using kickboard but i worry i either drop the kickboard and get tired and not get far atall. Water is also cold here in nz which can lead to difficulty moving amd WAY LONGER TIME to drown arggh. I dont want brain damage because i couldny get far enough not to mention avoiding boats. Fkn hell. If only someone had a boat...
A life vest (Ironic, I know) would help you float/swim to your desired distance, and allow you to simply float in place and rest.
Flippers to make swimming faster and easier.
Most kick/bodyboards have a leash attached to them with a velcro cuff that you can secure to your wrist or ankle so the board can't float away.
A wetsuit would help to provide insulation against cold temperatures, making it easier to stay warm.
None of these things would attract attention or suspicion by themselves or combined, and may in fact help you avoid attention or suspicion because people will see that you are using safety equipment and most likely know what you are doing.