Aside I'm not much an expert as well but, from DC to AC we are pretty efficient, around 98% of energy get converted. But the other way round it's pretty inefficient, meaning a loss around 30%. So while your p.v. it's pretty efficient in generating AC, your car it's pretty inefficient generating DC from AC to recharge. You heat pump would gain as well.
To be clear I do not advocate DC for any DC home appliance like washing machines or dishwashers, just for energy intensive appliances like big heat pumps and car chargers. Not more.
Try to imaging how well you could run if you have a small battery, as an expensive UPS for the home when you are not there (ventilation, homeservers, fridge(s)/freezer(s) etc) and when you are at home, thanks to a let's say 70kWh battery you can also run your heating in winter in case of a blackout...
In the end it's the very same power circuit, why not? 300€ extras in breakers to run my heat pumps more efficiently? No issue, they'll pay back countless more.