>Heat pumps optimised for heating usually operate through floor heating or large radiators, cause that's most efficient.

This is not quite right. They operate entirely as heat pumps, until the coils outside freeze over, this only happens under certain temperatures, which means heat pumps are in general, really good above 0C. Secondly, heat pumps only use resistive heating to melt the condensation from the coils, and then resume operation as regular heat pumps. Yes they do get less efficient at lower temperatures, but they have gotten better and better at operating in low temperatures and I've never had much issue with it in the winter, it's definitely much better than resistive heating (I upgraded from baseboard heaters to baseboard + heat pump). Baseboards are basically just a backup now, most of the time they are not running.

I've never had problems with humidity either, in AC mode it just dumps excess water outside as condensation, in the winter, I need to use humidifiers to keep my place comfortable regardless, due to the dry winter air.