You dont need to suppose & consider the possibility of this type of fresh air system.
In Japan they call it a Lossnay energy recovery system.

The Lossnay core heat exchanger can recover / transfer latent heat as well as sensible heat from incoming fresh air to outgoing extract air.
So it is an energy recovery system where as a standard plate heat exchanger is a heat recovery system as it only transfers sensible heat.

The technology regarding the Losnnay core is a bit ' complicated ' so I shall let you do your own investigations regarding this rather (as I am sure you already have) than write pages of tech stuff.

I just pulled an old Lossnay tech manual out of the archive & quote this as an example from the manual.

Outdoor fresh air
32 deg c DB, RH 70%, Absolute humidity 21.1 g/kg, enthropy 86.2 KJ/kg
Indoor air to be exausted
27 deg C DB, RH 50%, Absolute humidity 11.1 g/kg, enthropy 55.3 KJ/kg

These two airflows pass in the Lossnay core but do not mix.
The sensible & latent energy is transfered with the following result for the incomming fresh air.
Supply air
28.3 deg C DB, RH 63.1 %, Absolute humidity 15.3 g/kg, enthropy 67.4 KJ/kg.

The fresh supply air is ducted to indoor units of split systems & VRV / VRF systems which cool & dehumidify further as required for % fresh air & the internal room load.
The electronic controls for this system is fully integrated for use with VRV/VRF system controls.

The major manufactures also make this kit with a built in VRV/VRF cooling coil which can further cool/heat the supply air within the unit & then supply to VRV/VRF indoor units.

In the UK this type of fresh air heat / energy recovery is standard for all office blocks & hotel applications & some other applications but the main advantage in our cooler climate is winter pre heat of incomming fresh air & we have always found that it works very well.

For example in a hotel application each hotel room will have a small VRV / VRF ducted indoor unit in the ceiling & will have a small volume of ducted fresh air from the lossnay.

Please explain to me why this system is no good for your high humidity application other than the fact that it comes from Japan.